chemistryadventure by ChemistryAdventure

22.99

sodium

6.94

132.91

cesium

francium 223.02

85.47

rubidium

39.10

K potassium

lithium

40.08

103

174.97

Lutetium

cerium 140.12

Pr Pa

263.12

seaborgium

106

183.85

tungsten

Chlorate ClO3-

Chloride Cl-

Bicarbonate HCO3-

Bisulfate HSO4-

uranium 238.03

Carbonate CO32-

Bromide Br-

231.04

protactinium

Np 237.05

neptunium

promethium 144.91

264.12

bohrium

107

186.21

rhenium

technetium 96.91

Am americium 243.06

europium 151.96

(268)

Meitnerium

109

192.22

iridium

rhodium 102.91

cobalt 58.93

Group 9

111

Cm curium (247)

gadolinium 157.25

(281)

Dichromate Cr2O72-

Fluoride F-

gold 196.97

silver 107.87

copper 63.55

Group 11

Uub

Cf californium (251)

dysprosium 162.50

Ununbium (285)

112

mercury 200.59

cadmium 112.40

metal

Nitride N3-

Nitrate NO3-

26.98

indium 114.82

Uut

114

Uuq

207.19

Pb lead

Uup

208.98

bismuth

115

Antimony) 121.75

Sb tin 118.69

Sn 50

74.92

As 72.59 51

30.97

phosphorus

14.01

arsenic

Group 15

nitrogen

116

Uuh

polonium (210)

tellurium 127.60

selenium 78.96

32.07

sulfur

16.00

Group 16

oxygen

-3 -2

germanium

28.09

silicon

257.10

fermium

100

Er erbium 167.26

(256)

mendelevium

Phosphate PO43-

No (254)

nobelium

102

ytterbium 173.04

Permanganate MnO4-

Perchlorate ClO4-

Oxide O2-

Tm thulium 168.93 101

Nitrite NO2-

einsteinium (254)

carbon 12.01 14

+4, -4 Group 14

Valence electrons:

-1

Group 17

iodine 126.90

Uus

117

(210)

astatine

79.91

bromine

35.45

chlorine

19.00

fluorine

halogens

Group 18

Noble gases

Thiosulfate S2O32-

Sulfate SO42-

Sulfide S2-

nonmetal

Atomic mass

Manmade

Solid Liquid Gas

Symbol:

metalloid

metal

44.96

scandium

Atomic number

Phosphide P3-

to 103

to 71

name

Uuo

(220)

radon

xenon 131.30

118

39.95

Ar argon

krypton 83.80

neon

20.18

helium 4.00 10

ununtrium ununquadium ununpentium ununhexium ununseptium ununoctium (289) (295) (284) (289) (288) (293)

113

204.37

thallium

69.72

gallium

164.93

Hypochlorite ClOIodide I-

boron 10.81

aluminum

Group 13

Holmium

Hydroxide OH-

berkelium (249)

terbium 158.92

(272)

zinc 65.37

Group 12

Thallium Tl 204.38 Thorium Th 232.04 Thulium Tm 168.93 Tin Sn 118.71 Titanium Ti 47.87 Tungsten W 183.84 Uranium U 238.03 Vanadium V 50.94 Xenon Xe 131.29 Ytterbium Yb 173.04 Yttrium Y 88.91 Zinc Zn 65.41 Zirconium Zr 91.22

Darmstadtium roentgenium

110

195.09

platinum

palladium 106.40

Chromate CrO42Cyanide CN-

nickel 58.71

Group 10

Radium Ra 226.03 Radon Rn 222.02 Rhenium Re 186.21 Rhodium Rh 102.91 Rubidium Rb 85.47 Ruthenium Ru 101.07 Rutherfordium Rf 261.11 Samarium Sm 150.36 Scandium Sc 44.96 Seaborgium Sg 266.12 Selenium Se 78.96 Silicon Si 28.09 Silver Ag 107.87 Sodium Na 22.99 Strontium Sr 87.62 Sulfur S 32.07 Tantalum Ta 180.95 Technetium Tc 97.91 Tellurium T6 127.60 Terbium Tb 158.93

Chlorite ClO2-

plutonium 244.06

samarium 150.41

265.13

hassium

108

190.20

osmium

ruthenium 101.07

42 molybdenum 95.94

praseodymium neodymium 140.91 144.24

262.11

dubnium

105

180.95

tantalum

niobium 92.91

Group 8

iron 55.85

Group 7

chromium manganese 52.00 54.94

Bromide Br-

thorium 232.04

261.11

rutherfordium

104

178.49

hafnium

91.22

vanadium 50.94

Ammonium NH4+

actinium 227.03

zirconium

titanium 47.90

Group 6

Bisulfite HSO3-

lanthanum 138.91

262.11

6d lawrencium

yttrium 88.91

scandium 44.96

Group 5

Mercury Hg 200.59 Molybdenum Mo 95.94 Neodymium Nd 144.24 Neon Ne 20.18 Neptunium Np 237.05 Nickel Ni 58.69 Niobium Nb 92.91 Nitrogen N 14.01 Nobelium No 259.10 Osmium Os 190.23 Oxygen O 16.00 Palladium Pd 106.42 Phosphorus P 30.97 Platinum Pt 195.08 Plutonium Pu 244.06 Polonium Po 208.98 Potassium K 39.10 Praseodymium Pr 140.91 Promethium Pm 144.91 Protactinium Pa 231.04

Transition metals: 2 valence electrons

Meitnerium Mt 268.14 Mendelevium Md 258.10

Hafnium Hf 178.49 Hassium Hs 265.13 Helium He 4.00 Holmium Ho 164.93 Hydrogen H 1.01 Indium In 114.82 Iodine I 126.90 Iridium Ir 192.22 Iron Fe 55.85 Krypton Kr 83.80 Lanthanum La 138.91 Lawrencium Lr 262.11 Lead Pb 207.19 Lithium Li 6.94 Lutetium Lu 175.00 Magnesium Mg 24.31 Manganese Mn 54.94

2011 www.chemistryadventure.com

Acetate CH3CO2-

(and NH4+)

common anions

226.02

radium

barium 137.33

87.62

strontium

calcium

Group 3

Group 4

ActiniumAc 227.08 Cesium Cs 132.91 Aluminum Al 26.98 Chlorine Cl 35.45 Americium Am 243.06 Chromium Cr 52.00 Antimony Sb 121.75 Cobalt Co 58.93 Argon Ar 39.96 Copper Cu 63.55 Arsenic As 74.92 Curium Cm Astatine At (210) Darmstadtium Ds (281) Barium Ba 137.33 Dubnium Db 262.11 Berkelium Bk (249) Dysprosium Dy 162.50 Beryllium Be 9.01 Einsteinium Es 252.08 Bismuth Bi 208.98 Erbium Er 167.26 Bohrium Bh 264.12 Europium Eu 151.96 Boron B Fermium Fm 257.10 Bromine Br 79.91 Fluorine F Cadmium Cd 112.40 Francium Fr Calcium Ca 40.08 Gadolinium Gd Californium Cf (261) Gallium Ga Carbon C 12.01 Germanium Ge19.00 Cerium Ce 140.12 Gold Au 196.97

24.31

magnesium

9.01

beryllium

Group 2

Alkaline earth metals

(H is a nonmetal)

hydrogen 1.01

Group 1

2 valence electrons

Monovalent cations: Group 1, Ag: +1 Group 2, Zn: +2 Group 3, Al: +3

Alkali metals

1 valence electron

Periodic Table of the Elements

nonmetal



1   0.01097   2    w = wavelength in meters inner = inner shell # outer = outer shell #.

1 1

6. Periodic table; 7. Bonding 8. Reactions: No formulas 



Balmer formula :

5. electrons s = wf s = the speed of light = 3 x 108 m/s w = wavelength in meters f = frequency, per second.

3. Matter, 4. atom: no formulas 

K = Kelvin; OC = degrees Celsius

K = OC + 273

error x 100 accepted value

Temperature:

% error 

2. Data

d = density; m = mass in g; v = volume in mL 1. SI unit prefixes giga Billion (109) mega Million (106) kilo Thousand (103) deka Ten (100) deci Tenth (10-1) centi Hundredth (10-2) milli Thousandth (10-3) micro Millionth (10-6) nano Billionth (10-9) pico Trillionth (10-12)

Density:

1. Introduction to chemistry

C  273

molB gB x  gB mol A molB

PV PV 1 1  22 T1 T2

22.4L/mol or 1 mol/22.4 L

PV = nRT

Combined Must use Kelvin for T

T1 T2  P1 P2

Avogadro’s Principle Only at STP

Ideal Gas Law Must use L (Volume), atm (Pressure), mol (n), K (Temp). R = 0.0821 L atm/mol K.

Gay-Lussac Must use Kelvin for T

mol A molB gB x x  gB gA mol A molB

10. Gas Laws Formula Law Boyles PV  PV 1 1 2 2 Any units ok Charles T1 T2  Must use Kelvin for T

gA x

g– g conversions:

mol A x

Gram – mol conversions:

(volumestandard )(molaritystandard ) volumeunknown

molarityunknown 

titration:

pH + pOH = 14

10-pOH = [OH-]

pOH = -log[OH-]

10-pH = [H+]

pH = -log[H+]

Kw = [H+][OH-] = 10-14

Ka for example of HCl = [H+][Cl-]/[HCl]

14. Acids and Bases Formulas

11. Energy: q = mcDT q = heat, m = mass, T = temp cwater(l) = 4.184 J/goC cwater(s) = 2.03 J/goC cwater(g) = 2.01 J/goC DHvap = 2260 J/g; DHfus = 334 J/g At 1 atm: Water boils/condenses at 100oC Water melts/freezes at 0oC 1 Nutritional Calorie = 4184 Joules = 4 BTU = 1000 calories = 0.0016 kilowatt hours DG = DH-TDS DG = change in free energy DH = change in enthalpy T = temperature DS = change in entropy

Formulas

mol B mol A x  mol B mol A

Mol-mol conversions:

9. The mole = 6 x 1023

K 

Boiling point elevation and freezing point depression: DTf = Kfm . pm DTb = kbm . pm DTf = change in freezing temp; DTb = change in boiling temperature; Kf = freezing point constant; Kb = boiling point constant; m = molality; pm = particle molality

1 atm = 760 mm Hg = 14.7 psi = 101.3 KPa 1 L = 1000 mL Tcelsius + 273 = Tkelvin

12. Solutions 1. Percent concentration by volume (%v/v) = volume of solute x 100 volume of solution 2. Percent concentration by mass (%m/m) = mass of solute x 100 mass of solution 3. Molarity (M) = moles of solute Liters of solution 4. molality (m) (L1 only) = moles of solute Kilograms of solvent 5. Mole fraction (X) = moles of solute Moles of solution Concentration and dilution 6. C1V1 = C2V2 where C1 and C2 are concentrations; And V1 and V2 are volumes 7. Henry’s Law: Solubility is proportional to Pressure S1/P1 = S2/P2

13. Rates Reaction rate = Dconcentration/Dtime Collision Theory: For 2 molecules to react, they must collide, and with enough force, and in the right locations on the molecules for the reaction to occur. M = Molarity = moles per liter = moles/liter

sample

Odor

Flame color

Other observatio ns

Unkno wn #

Water

Methanol

3ethanol

propanol

isopropanol

butanol

Odor

Flame color

Other observ ations



O Controls: Standards For comparison all experiments need these:

What is a positive control?

Example:

Oh heck I know that The 4-letter mnemonic for this simplified scientific method

What is a positive control?

Example: 4

H H C C C H H

O H H

C H

O C C

H O H

H H C C H O

Br Br

C C

O alkane

alkene O

NH2 amine

ether

alkyne O

O O

aldehyde

ketone

alcohol O

ester

NH amide

carboxylic acid

O NH

Data



•



measurement

SI Units unit

symbol

size

Unit Prefixes Prefix

mass volume distance amount brightness current time

kilogram liter meter mole candela ampere Second

kg L m mol cd A s

nano (n) micro (m) milli (m) centi ÂŠ kilo k) mega (M) giga (G)

billionth millionth thousandth hundredth thousand million billion

3. Complete the table Unit of measurement Length Mass Temperature density

6. Complete the table. Prefix Symbol

We usually use

Factor

Scientific notation 10-9 10-6 10-3 10-2 103 106 109

But SI units require

Scientific notation

example

Giga mega 1,000 centi 10-3 micro

Microgram n

•

• •

• • •

•

• • • •

unit 3

How do we find out what everything is made out of?

Unit 3

What is a tomato, mustard leaf, and a strawberry made out of?

ook around you. What do you see? In front of you

are all kinds of stuff- all sorts of matter. Some of this matter you can see, and there’s more that you can’t. Some substances, such as those in your body, are undergoing transformations as we speak. And most of it is all mixed together, which complicates things further. What’s it all made out of? It’s a big mess. What we need to make sense of it is a way to sort things out. Our primary goal for this unit is to classify the matter that is all around us. First, we’ll consider what we can say about mixtures. As you might guess, not very much…it varies from sample to sample. So, we will explore some purification techniques. We will spend the remainder of our time finding out what we can about pure substances- these are the materials that the universe as we know it is made from. And since nearly all understanding of matter begins with pure substances, purification is the first step in chemical research. Here’s the plan: Lesson 1: Separation Lab Lesson 2: Leaf Lab Lesson 3 Matter Lecture Lesson 4: Review Lesson 5: Matter test.

A Liquid Chromatograph-Mass Spectrometer (LCMS) can take a complex mixture, separate it, and identify each substance. Shown above are the major components of a tomato (a), mustard leaf (b), and a strawberry (c), with some individual substances (d-f) shown below based on their mass spectrum. Learn more by clicking on the image.

Table of contents

Separation Lab Some separation methods to consider

Chemists typically spend more than half of their time purifying substances- separating them into their individual pure components. As a chemist it reminded me of cleaning up a mess at home. In this lab you will be given a mixture of 5 solid ingredients. Typically, these are sand, sugar, salt, iron filings, corn kernels, and pebbles. This year, they are: 1: __________ 2: __________ 3: __________ 4: __________ 5: __________ 6: __________

Separatory funnel

filtration

Your goal is to separate all ingredients of your mixture quantitatively, and analyze your results. You will be graded based on your choice of methods, your report, and percent error: how close your amounts are to the actual amounts provided.

forceps

evaporation

decant

boiling

Homework: Discuss this with your partner and come up with a plan. Write it as a diagram on the next page. You are welcome to use any equipment in the lab as long as you work safely and have it approved by me. Be ready to begin your experiment the following day. You will be allowed to dry any wet samples overnight.

Note that no student has yet come up with a quantitative method to separate salt from sugar.

chromatography

Invent your own

Sample Separation Scheme pebbles Iron filings Method salt sugar sand

sand Iron filings pebbles

pebbles

Iron filings Method salt sugar

salt

Method Iron filings

Iron filings salt sugar

salt Method sugar

Most common errors: -No separation or only partial separation of salt and sugar. -Samples still wet after overnight drying.

Separation lab (continued) Homework: Draw a neat diagram outlining your separation procedure, using the scheme shown on the following page. Note that you will have 60 minutes of class time only over two days to complete your separations.

Sand is an ingredient, but is not actually pure, as it contains hundreds of substances in addition to quartz (SiO2)

Once you have the stamp of approval, begin your separations. Time your work so that any sample drying takes place overnight. When you are done place each sample in a labeled plastic bag, and ieach ndividual bag in a final plastic bag- your instructor will model it for you. You will be graded based on the purity and amount of each sample. Fill in the data table and complete the Analysis section below.

Separation Lab: Data Mass of mixture

________ g

Mass of component 1 (__________)

________ g

Mass of component 2 (__________)

________ g

Mass of component 3 (__________)

________ g

Mass of component 4 (__________)

________ g

Precision: 1 point off for each percent error

_____ /10

Mass of component 5 (__________)

________ g

______ 10

Mass of component 6 (__________)

________ g

Sample Purity (by inspection)

Total mass of separated components

_______ g

Neatness and accuracy of report and analysis

_____ /10

Total

_____ /30

Percent Error

________ %

Your Score

Analysis: Write a paragraph summarizing your experiment, and reflect on the results. Be sure to include recommended improvements if you were to repeat the process. Use additional paper if necessary.

Lab 3.2 The matter all around us is rarely in a pure form; most of what is around us are mixtures. Perhaps the most complex mixtures are those in living things. To understand what is in a mixture we must separate the individual substances contained in a mixture. In our very first experiment you each planted a seed and by now you should have several leaves. The goal of this experiment is to isolate some pure substances from that leaf. If you have need to, bring in some fall leaves from home. Every leaf contains thousands of individual chemicals. We’ll focus on three visible groups with characteristic fall colors: the carotenes, xanthophylls, and chlorophylls. Their chemical structures and typical colors are shown on the right

1. 2.

Which is more greasy (“hydrophobic”): the carotenes or the xanthophylls? Which is more greasy: chlorophyll A or B? Why?

Background: Chromatography (“color writing”) is a powerful tool for purifying mixtures. We will use paper chromatography to isolate the visible substances in a leaf. To do this we will make a thin paste of leaf goo using a powerful solvent (methanol), then paint it on chromatography paper, which is our “stationary phase. We then place it in a jar that has some organic solvent on the bottom (our “mobile phase”, and allow the solvent to move up the paper, separating the mixture based on the adherence to the paper, and the solubility in the solvent. Your task is to find a solvent system that will separate the mixture. Watery solvents such as methanol or acetone tend to dissolve everything and move the mixture rapidly. Greasy solvents such as hexane don’t tend to move the mixture much at all. Try a few combinations until you get nice separation, like the chromatogram shown below. Not the identity of each band, and how the distance traveled by the substance is measured using Rf value, where all the way up to the solvent front has a value of 1, and the baseline has a value of zero.

Carotenes

Rf = 1.0

Xanthophylls Rf 0.37 mystery substance Rf 0.32 Chlorophyll A Rf 0.21 Chlorophyll B Rf 0.16

Carotenes: Gold to Orange

Xanthophylls: Light Yellow

Chlorophyll A: Forest Green

Chlorophyll B: Olive Green

Using the techniques described in this lab report and demonstrated by your instructor, find a solvent system that provides optimum separation of visible leaf constituents.

Tape your chromatogram here. Identify each band and measure its Rf value.

Tape your best chromatogram to this lab report and measure the Rf value of each visible substance. Note that your values do not have to match those on the previous page.

Score: Prelab questions: _____/3 Separation: _____/3 Identification: ____/3 Rf measurements: _____/3 Total: ___/12

Solvent system used: _____% ____ _____% ____



Classifying Matter

ws 3.1

What is everything made out of? Our essential question for this course: To say that the universe is made out of matter is true, but doesn’t provide much detail. It would help to classify mater.. Let’s start with elements. The universe as we know it has about 100 elements. Occasionally we see them in their isolated form- for example an engagement ring may be pure gold (Au), with a diamond on it, which is pure carbon (C ).

More often we see the elements bonded together to form molecules, such as water (H2O) or table salt (NaCl). Sometimes called compounds,* molecules are made out of multiple elements which are bonded together and they have constant physical properties. For example, water freezes at 0 oC, and table salt melts at about 2000 oC.

What is everything made out of?

If we look closely at the things around us, we find that most of them are mixtures of molecules. Drinking water, for example, is mostly made out molecules of water, but also has some molecules of salts (like NaCl) and may have be fluoridated as well. Classify each of the materials below as an element, molecule, or mixture. The examples below should help get you started. It’s OK if you miss a few…this is to get us thinking about what things are made out of. A key will be passed out after you complete this. Element, molecule, or mixture?

What is a diamond ring made out of?

A. Silver Answer: Silver is an element (Ag). B. Air Answer: air is a mixture of nitrogen (an element), oxygen (an element), and, among other things, carbon dioxide (a molecule). C. Ice Answer: ice the solid form of water, which is a molecule (H2O).

Classify the 19 materials on the next page, then check the answer key to see how you did.

*You

should be aware that many texts differentiate between molecules and compounds. In this class we won’t go there. If you’d like to see the confusion that it can lead to, click here or here.

Element, molecule, or mixture?

Material A. Silver B. Air C. ice 1. Mud 2. sugar 3. steam 4. Baking soda 5. Alumninum foil 6.brass 7. blood 8. Bubble gum 9. gatorade 10. chalk 11. glass 12. Soy sauce 13. grasshopper 14. gasoline 15. urine 16. snow 17. milk 18. tobacco 19. Pencil lead (graphite)

Element ? 

Molecule?

Mixture? 



20. Look around you. Try to find examples of elements, molecules, and mixtures in front of you right now. 1. An element in front of me:______ 2. A molecule in front of m:________ 3. A mixture in front of me:________ 21 (L1, honors only) Use the following 6 definitions to make a classification chart similar to the one at the end of unit 1. A sample to get you started is at the bottom right of page 18. Matter: Anything with mass and space. Element: A substance with a fixed number of protons Molecule: Atoms bonded together Compound: Different atoms bonded together Mixture: More than one substance Substance: A pure form of matter each of the 7 words below on your chart as examples. Consider if some should go in more than one place.. Also ask yourself if pure elements are bonded together. Oxygen (O2) Water Iron Carbon Diamond Graphite Sodium chloride

Humans love to classify everything.

Matter classification chart (L1, honors only)

ws3.3

A walk on the beach

Introduction to Matter Summary Worksheet

Crystalline Amorphous Matter Substance Compound Solid Gas Heterogeneous

Homogeneous Liquid crystal Liquid Sublimation Deposition Boiling Melting Condensation

Chemical Physical Silicon Oxygen Ozone Precise accurate

While walking down the beach one day, I spied a small object. I noticed it has both mass and took up space, so I was sure it was ___________. I picked it up and took a look at it under a magnifying glass. I could not see any impurities in this glassy object, therefore I was pretty sure it was _____________________. I assumed it was pure, so I classified it as a ____________________. I took it home and heated it over a fire, but it did not melt, so I canâ&#x20AC;&#x2122;t really say anything about that __________________(physical, chemical) property. I hammered it and it did not flatten; it is not _____________. I tried to stretch it and could not; it is not _______________. This material is a colorless solid. By the way, The other states of matter are ___________, _____________, and _____________. A few believe that _____________ represent a fifth state of matter, and this phase could either be in a ____________ or _____________ state. My little rock is just a simple solid. Since it is shiny I could say it is ___________. If I had the right equipment I could heat it up to a liquid (_________ it), or perhaps even heat it further from a liquid to a gas (_______________). Itâ&#x20AC;&#x2122;s possible that when I heat it up it might go directly to a gas (_______________), but I doubt it. I do know that iodine vapors can cool directly to form a solid (_______________), but that has nothing to do with my story. I happened to have some hydrofluoric acid kicking around, and when I dropped in my substance to that nasty acid, it dissolved. That _____________(physical, chemical) change was weird. I sent it out to an analysis lab and they told me that my 600 milligram sample consisted of 280 milligrams of Si (_______________), and the rest was O (_______________). The percent composition of my sample is therefore _______% Si, and ________% O. And I thought my substance was a pure element, but really it is a just a _________. I submitted several similar samples I found at the beach and they all gave exactly the same analysis; this data is very ___________. I assume the people at the lab know what they are doing so it is probably __________ as well. L1 and honors students know that if I could prepare a solution of my substance I could puriy it and have the minor impurities identified using a single machine known as a ___________. But Iâ&#x20AC;&#x2122;m pretty sure I know what it is already. My substance is______________.

ws3.4

I need it Pure

Modern Purification and identification methods worksheet After listening to the matter slideshow, especially the last two slides on modern methods of sample purification and identification, answer the questions below using some but not all of the words below

Place an I in front of each term above that refers to compound Identification, and a p in front of methods used for Purification 1. Which method is best for separating oil from water? __________________________ 2. Which method is best for separating two liquids whose boiling points only differ by one degree Celsius? ________________ 3. Which method is appropriate to separate 5 mg of a solid organic substance? _______________ 4, I’d like the elemental composition of a pure metal. A good method would be______________ 5. I’d like to separate a separate a sample of Martian Air into it’s individual components…a good choice would be:______________________________ 6. This method of sample identification is used for organic compounds, and although it provides a nice “fingerprint of the substance, has been largely replaced by more informative methods such as___________ 7. This method of sample identification creates predictable peaks based on the composition of the elements next to the point in question._________________________ 8. This method of sample identification produces a molecular ion which is a good measure of the molecular weight of the substance._______________________________________ 9. This is an old method of purification still in use, gives incredible sample purity, and was used in the rock candy experiment __________________________________ 10. This will do for separating oil and water __________________________________ 11. For the separation of complex mixtures which can be dissolved in a solvent, this method is hard to beat._________________________________________ 12. Used in the leaf lab, this method will separate a crude sample into many individual substances but is rarely used professionally. ____________________________ 13. This is the ultimate solution: it will separate and identify just about any solution, no matter how complex.___________________________________

How to ace the Matter test

Howtoaceitunit3

In this our third unit we learned how to purify and classify matter. Matter in its natural state is a mixture of substances, and to study them we purify and identify them, and determine their properties. The mixtures may look pure (homogeneous) or many things may be visible (heterogeneous). The pure substances occasionally are composed of only one element, but more often are molecules that consist of multiple elements bonded together. There are a nearly infinite number of individual substances on earth, and chemists have learned how to mak evirtually any new substances (though not always very quickly) of their own design.

We have seen how substances may be classified based on how their atoms are arranged (for example functional groups such as aldehydes, ketones, etc.). They may also be grouped into their 5 physical states, their physical, or their chemical properties. A chemist spends the majority of his or her time purifying mixtures, and we spent some time doing that. We used basic techniques such as decanting, filtration, distillation, and chromatography to isolate some pure substances from a mixture. L1 and honors students explored the modern equipment used for separations including high performance liquid chromatographs and spinning band distillation devices. All students learned basic methods to identify pure substances such as odor, melting point, and conversion to known compounds. L1 and honors students also learned about modern spectroscopic methods to identify substances such as nuclear magnetic resonance (NMR) spectrometers. Finally, they had a glimpse at the future with some state of the art devices that can purify a mixture and identify each substance in it such as a LC-MS (liquid chromatograph-mass spectrometer). To ace this test be sure to understand the packet, including all lab experiments, slides, and worksheets. Go online and watch the screencasts of the slides if necessary. Be ready to separate a mixture if given one. Take a brief look at the first two units, since they are fair game on a test. Review your notes from your lab notebook, including all demonstrations and chalk talks. Finally consider the significance of the long term experiments we have been monitoring- the rock candy lab, and the seed lab. In our next unit we will zoom in enormously from our macroscopic view of matter and will ask ourselves what the smallest building blocks of matter are- this is the atom unit coming up next. Be able to provide detailed answers to the questions below. Have a thorough understanding of the concepts below. Be able and ready to separate a mixture if given one.

1. What is matter? Matter is_____________________

14. How to separate mixtures a. Sugar from sand

2. What is a substance? A substance is a __________ _________ or ____________

b. Iron from sand

3. What is a physical property?

d. Blue ink from black ink

c. Water from the ocean

4. What is a chemical property?

15. What is an element?

5. How could I separate sand from aluminum powder?

16. What is a compound?

6. What are the 5 states of matter? 7. Where can I observe plasma? 8. What are liquid crystals? 9. What are the two types of liquid crystals and how do they differ?

17. Why is chromatography such a powerful method for the separation of chemical mixtures? 18. Draw a chromatogram of a sample that has a Rf of 0.75 19. What does HONC mean? 20. Draw propanol, C3H8O using both a structural and skeletal formula.

10. Describe the six conversions of matter states (boiling, meltingâ&#x20AC;Ś)

11. What is the law of conservation of mass? 21. Draw two isomers of butane, C4H10, 12. Define malleable and ductile and give examples of each. 13. Heterogeneous mixture = ___________________; homogeneous mixture =___________________ Homogeneous mixtures can be solid/liquid (______________), liquid/liquid (______________), gas/liquid (______________), gas/gas (______________), or even solid/solid (______________).

22. To put this unit in perspective, modify the conceptual diagram at the end of unit 1 to include the main concepts of the matter unit.

22. What is an atom? This is our next unit.

urushiol

Toxicodendrons radicans (poison ivy)

Poison Ivy (Toxicodendron radicans, shown at left) produces the urushiol class of allergens, including the one shown

The Atom Unit 4

How do we know that the world is made out of atoms? A historical approach. Page 90 Unit 4: the atom

History of the atom worksheet

ws 4.1

Complete this worksheet after listening to the presentation on the history of the atom from 400 BC to 1907 AD. Refer to the notes on your slides if you need to for each question. 1. What is the essential question for this course? 2. What is the essential question for this unit? 3. What would you need to see, know, or observe to become convinced that atoms exist?

4. By now you have seen a presentation on some ideas and experiments concerning the atom from about 2400 BC to 1907. Fill in the table below to summarize the work and significance of some of the key players. name

Democritus

Aristotle

Ghazali

Lavoisier

Dalton

Thomson

Rutherford

Symbol

Contribution

5. How is Daltons model of the atom different from that of Democritus?

6. Draw a picture of the Cathode Ray tube used by Thomson, identifying each component. Show 2 experiments that indicate the green light in the tube is in fact not light.

7. Light is a form of electromagnetic energy and has no mass. Compare that to the green light in the cathode ray tube.

8. How might the gold foil experiment suggest the shape of an atom?

9. How big is an electron compared to a hydrogen atom?

10. Draw a figure and explain Rutherfordâ&#x20AC;&#x2122;s Gold foil experiment:

11. Lavoisierâ&#x20AC;&#x2122;s experiments indicated that mass is never lost when chemical reactions occur. Daltons experiments suggested that elements come in different sizes, and they combine in simple ratios. Thomson showed there is something smaller than hydrogen, and Rutherford showed that there is a lot of empty space in matter. Based on those experiments and a hunch that the atom may resemble our solar system, the early 20th century model of the atom is the Jimmy Neutron symbol. To understand the atom is to understand all matter on its most basic level. What did they still NOT know about the atom at this point? List as many things as you can.

Atomic Bookkeeping Worksheet

ws 4.2

Atomic Particles, Atomic Number, Mass Number, Ions, and Isotopes Here are some quick facts to help you keep track of the names and numbers associated with the atom:

Protons are in the nucleus, each has a +1 charge, and identifies the element. Neutrons are in the nucleus, each has no charge, and determines the isotope. Electrons are outside the nucleus, each has a -1 charge, and determines the reactivity. Atomic Number is the number of protons. Mass number is the number of protons + neutrons Average atomic mass is the averaged mass for a mixture of isotopes An ion has either more or less electrons than protons, so it is charged. Isotopes vary only in the number of neutrons for an element. 1. Pick an element, any element. My element has the symbol _______, which stands for ____________. It has ______ protons, and when uncharged also has _________ electrons. The average atomic mass of this element is ________ atomic mass units. If it has one extra electron, this would give it a _____ charge. If one atom had two more neutrons than protons, the mass number would be ________ atomic mass units. 2. Fill in the blanks below: ____________average atomic mass ____________chemical symbol ____________chemical name ____________atomic number

Hydrogen 1 H 1.008

3. Complete the following table: Element O (oxygen) Zn (zinc)3+ Sn (tin)Fe (iron)3+ C (carbon) H (hydrogen)+ Sg (seaborgium)

Number of protons 8

Number of electrons

4 What is an isotope? 5. What is the difference between mass number and atomic number?

Average atomic mass 15.999

1. Complete the following table:

Atomic mass/average atomic mass worksheet Element O (oxygen) Zn (zinc) Sn (tin) Fe (iron) C (carbon) H-(hydride) Note the negative sign! Sg (seaborgium)

Number of protons 8

Number of electrons 8

Number of neutrons 9 37

Mass number 17 118

30 14 0

266

2. Mass number and atomic number are easy to confuse. To determine atomic number one only needs to know the number of _____________, whereas the mass number also includes the number of_____________. 3. Chlorine has two naturally occurring isotopes, Cl-35 and Cl-37. The lighter isotope is _____ which contains _____ protons and _____ neutrons. The heavier isotope is _______ with _____ protons and _____ neutrons. 4. Here is a problem that is solved for you. As you read the problem, imagine how you could solve it without a calculator, then see how it is done, and apply the solution to #5. An imaginary element X has two isotopes, one with a mass of 20 atomic mass units (amu), and the other with a mass of 22 amu. They both occur with equal (50%) abundance. What is the average atomic mass of X? Solution: (0.5)(20) + (0.5)(22) = 21 a.m.u. 5. What would the atomic mass of element X above be if the abundances of X-20 was 25%, and the abundance of X-22 was 75%? Solution (fill in the missing numbers: ( )( ) +( )( ) = _____ a.m.u. 6. Silver has 2 isotopes. One has a mass of 106.905 amu (52%) and the other has a mass of 108.905 amu (48%). What is the average atomic mass of this isotopic mixture of silver?

Isotopes, ions, atomic mass, and average atomic mass worksheet

ws4.3

The number of protons, electrons, and neutrons is usually symbolized in an element box in the following manner: For example: 235 41 Mass number 19 2+ (p + + n 0)

Charge (p + + e -)

Na+

F-

9 protons 10 neutrons 10 electrons

atomic number (p + )

20 protons 21 neutrons 18 electrons

92 protons 143 neutrons 92 electrons

Once the number of each atomic particle is known, it is an easy matter to identify isotopes (atoms that vary only in the number of neutrons) or ions (atoms that do not have the same number of protons and electrons). 1. Fill in the blanks

___protons ___ neutrons ___electrons

238

___protons ___protons ___ neutrons ___ neutrons ___electrons ___electrons

238

___protons ___ neutrons ___electrons

___protons ___protons ___ neutrons ___ neutrons ___electrons ___electrons

7 protons 9 neutrons 8 electrons

8 protons 105 protons 132 neutrons 8 neutrons 106 electrons 8electrons

2. Which pairs of elements are isotopes?

3. Which elements are ions? 4. Fill in the boxes below.

1 protons 0 neutrons 1 electron

23 protons 24 neutrons 22 electrons

5 protons 6 neutrons 8 electrons

5. Are the following pairs of compounds isotopes, ions, or different elements? Also, provide the full atomic symbol for each substance Example: a. Substance 1: 10 protons, 10 neutrons, 10 electrons: b. substance 1: 10 protons, 11 neutrons, 10 electrons Relationship: isotopes

c. Substance 1: 10 protons, 10 neutrons, 10 electrons d. substance 1: 9 protons, 10 neutrons, 10 electrons Relationship:________________ e. Substance 1: 10 protons, 10 neutrons, 11 electrons f. substance 1: 10 protons, 10 neutrons, 10 electrons Relationship:________________ 6. Determine the average atomic mass for the following imaginary elements, using the first question as an example.

Solved Example. Isotope 1: 4 protons, 4 neutrons. Abundance : 91% Isotope 2: 4 protons, 5 neutrons. Abundance : 9% Average atomic mass = sum of (abundances)(mass number) = (0.91)(8 amu) + (0.09)(9 amu) = 8.09 amu a. Isotope 1: 14 protons, 14 neutrons. Abundance: 62% Isotope 2: 14 protons, 16 neutrons. Abundance : 38% Average atomic mass =

b. isotope 1: 94 protons,104 neutrons. Abundance : 52% Isotope 2: 94 protons, 112 neutrons. Abundance: 48% Average atomic mass =

c. Isotope 1: 24 protons, 24 neutrons. Abundance : 40% Isotope 2: 24 protons, 25 neutrons. Abundance : 39% Isotope 3 : 24 protons, 28 neutrons abundance = 21%

3. Level One Only: Boron has two naturally occurring isotopes. Boron -10 (abundance = 19.8%; mass = 10.013 amu) and another isotope (abundance 80.2%). The average atomic mass of boron is 10.811 amu. What is the mass of the other isotope?

How to ace the Atom unit

Howtoaceitunit4

In this our fourth unit, we explored the atom. Our goal was to answer the question: How do we know that atoms exist? We began with a chronological study, starting with the ideas of Democritus, and ending with the discovery of the nucleus by Rutherford. We also considered what it would take to convince us that atoms in fact do exist, and we found evidence that atoms have been individually observed and moved. We then focused on the three primary subatomic particles. We considered their location, mass and charge, and this led to an understanding of atomic number, mass number, and average atomic mass. Finally, we applied this to isotopes, and finished with the band of stability- the ratio of protons to neutrons for a stable atomic nucleus. In our next unit we will focus on the subatomic particle that determines the chemical behavior of each element: the electron. To ace this unit you should review the powerpoint slides, the atom worksheets, and this study guide. You should also review the results of our Seeing the Atom project. Here are some quick questions on each topic we covered. 1. The history of the discovery of the atom: a. Aristotle and his four â&#x20AC;&#x153;elementsâ&#x20AC;? b. Democritus: symbol and what he got right c. Paracelsus: Symbol and contribution d. Lavoisier: Symbol, contribution, and his untimely end e. Dalton: symbol and his major contribution f. Thomson: symbol, what he discovered, device he used, evidence . g. Rutherford: symbol, and his key experiment 2. The 3 subatomic particles, their mass in atomic mass units (amu), and charges

3. Atomic number

Example: What are the atomic numbers for each element in baking soda, NaHCO3? Why can Magnesium never have 13 protons?

4. Mass number

Example: What is the mass number of an oxygen atom that has 8 neutrons and 9 protons?

5. Average atomic mass formula

Example: Element X has two isotopes. One has an abundance of 63% and an atomic mass of 10 a.m.u. The other has an abundance of 37% and an atomic mass of 15 a.m.u. What is the average atomic mass of element X?

6. Isotopes- definition (watch out for cases that are different elements, not different isotopes)

Example: How many protons and neutrons are present in an atom of Cs-111?

7. Ions- know how to calculate charge on an atom

Example: How many protons, neutrons, and electrons are present in an atom of C-13?

Example: Draw element boxes that show an example of a fluoride monoanion (-1), and a calcium dication (+2).

8. Nuclear stability

Example: Circle the stable isotopes: U-238 Po-208 C-14 9. Chemical symbols for elements 1-20

What are the symbols for

hydrogen, helium, lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, neon, sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, argon, potassium, and calcium,? 10. How do you know that atoms exist? Provide quantitative evidence in addition to imaging. Be sure to review the Seeing the Atom Presentations from each of you. Good luck on the test.



 

  



  

w

1 1   1 0.01097 2  2  2 n 

1 valence electron

2 valence electrons

Alkali metals

H hydrogen 1.01

Alkaline earth metals Group 2

(H is a nonmetal)

sodium

24.31

4s 5s

rubidium 85.47 55

cesium 132.91

6s 87

potassium 39.10

francium 223.02

calcium 40.08 38

strontium 87.62 56

barium 137.33 88

radium 226.02

Monovalent cations: Group 1, Ag: +1 Group 2, Zn: +2 Group 3, Al: +3

common anions (and NH4+)

Transition metals: 2 valence electrons

magnesium

22.99 19

Group 13

9.01

6.94

Group 3

scandium 44.96 39

yttrium 88.91

Lutetium 174.97 103

6d lawrencium

Group 4

titanium 47.90

4f 5f

lanthanum 138.91 89

actinium 227.03

hafnium 178.49 104

rutherfordium

Ce cerium 140.12

thorium 232.04

tantalum 180.95 105

dubnium

261.11

niobium 92.91

91.22 72

vanadium 50.94

zirconium

262.11

Group 5

262.11

Group 6

tungsten 183.85 106

seaborgium 263.12

protactinium

231.04

144.24

uranium 238.03

bohrium 264.12

promethium 144.91 93

neptunium 237.05

Group 9

cobalt 58.9 3 45

ruthenium 101.07

109

Group 11

nickel 58.71 46

iridium 192.22

Group 10

rhodium 102.91

osmium 190.20 108

iron 55.85 44

rhenium 186.21 107

Group 8

molybdenum technetium 96.91 95.94

140.91

chromium manganese 52.00 54.94

praseodymium neodymium

Group 7

copper 63.55

palladium 106.40

silver 107.87 79

platinum 195.09

110

gold 196.97 111

hassium Meitnerium Darmstadtium roentgenium (272) 265.13 (268) (281)

samarium 150.41 94

plutonium 244.06

europium 151.96 95

americium 243.06

gadolinium 157.25 96

curium (247)

terbium 158.92 97

berkelium (249)

Group 12

zinc 65.37

cadmium 112.40 80

mercury 200.59 112

Uub

Ununbium (285)

dysprosium 162.50 98

boron 10.81

72.59

Uut

lead 207.19 114

Uuq

arsenic 74.9 2

bismuth 208.98

Uup

115

selenium 78.9 6 52

Antimony) 121.75

tin 118.69

thallium 204.37

argon

35.45

39.95

Br bromine

Uuh

117

krypton 83.80

79.91 53

116

neon

20.18

chlorine

polonium (210)

19.00

tellurium 127.60 84

helium 4.00 10

sulfur 32.07

30.97

fluorine

16.00

phosphorus

28.09

Group 17

oxygen

germanium

iodine 126.90

xenon 131.30

Uus

118

astatine (210)

radon (220)

Uuo

ununtrium ununquadium ununpentium ununhexium ununseptium ununoctium (289) (295) (284) (289) (288) (293)

Holmium 164.93 99

Group 16

Noble gases

Group 18

-1 halogens

-2

Group 15

14.01

indium 114.82

113

-3 7

nitrogen

silicon

69.72

gallium 49

Group 14

aluminum 26.98

carbon 12.01

+4, -4

beryllium

lithium

metal nonmetal

Group 1

Valence electrons:

californium einsteinium (251) (254)

erbium 167.26 100

fermium 257.10

thulium 168.93 101

ytterbium 173.04 102

mendelevium nobelium (256) (254)

to 71

Atomic number

scandium

to 103

Symbol: Solid Liquid Gas

Manmade

name

44.96 Atomic mass metal metalloi d

nonmeta l

Name_____________________________ Period_________ Wavelength Worksheet

WS5.1

Please show your work, not just the answer ď &#x160;. If you look down from Diamondhead in Hawaii, you will see waves rolling in at a steady rate. Some days they are nicely spread apart, meaning they have a long wavelength. Other days they come in more frequently; this is more dangerous for the surfers. The surfers prefer the long wavelength days. They know that as the wavelengths get shorter, their frequency gets higher, and there is more energy- more danger â&#x20AC;&#x201C; to the high frequency waves. This is summarized in the diagram:

Light travels in the same way. It travels at a steady rate: about 300,000,000 meters per second, or 3 x 108 m/s. And as the wavelength decreases, the frequency must increase: Wavelength Formula Our eyes are really important to us, but they are kind of lame when you consider the tiny portion of light S = wf from the electromagnetic spectrum that theyincan detect: S = speed of light = 3 x 108 m/s w = wavelength meters (m) f = frequency in waves per second (Hz, or s-1) Wavelength Chart

We can use the wavelength formula and the chart on the previous page to understand things like radio stations, visible light, and sunburns (due to ultraviolet light). Our ultimate goal is to make the connection between light and the electron.

Example. What is the frequency of green light, which has a wavelength of 4.90 x 10- 7 m? Solution: s  wf; f 

s 3 x 10 8 m/s   6.12 x 10 14 s -1 w 4.90 x 10 -7 m

In addition to a scientific calculator, you will need to refer to the wavelength chart on the previous page to answer these questions. 1. An X-ray has a wavelength of 1.15 x 10-10 m. What is its frequency?

2. What is the speed and wavelength of an electromagnetic wave that has a frequency of 7.8 x 106 Hz? 3. A popular radio station broadcasts with a frequency of 94.7 megahertz (MHz). What is the wavelength of the broadcast? (1 MHz = 1,000,000 Hz)

4. Cable television operates at a wavelength of about 1300 nanometers. What is the frequency of that wave, and what region of the electromagnetic spectrum is it in? Is it dangerous? (Any wave more frequent than visible light is considered dangerous).

5. Which is more dangerous, a radio wave or ultraviolet light?

6. The moon is 234,000 miles from earth. Light travels at 3 x 108 meters per second, and there are 1.62 kilometers in a mile. When you shine a flashlight on the moon, how long does it take for the light to hit the moon?

7. The smallest particle of light is the photon. Max Planck discovered that the energy of light can be calculated, where it is simply equal to a constant number multiplied by the frequency of the light: What is the energy of a photon of green light? Light Energy Formula: (See question number 1) E = hf Where E is the energy of the light in joules h = Planck’s Constant = 6.626 x 10-34 joules .seconds f = the frequency of light in Hz (which is 1/seconds) 8. What is the energy of a photon of light with a wavelength of 2 meters?

9. Since s = wf, and E = hf, can we calculate energy using wavelength, by combining the two formulas? Please show the combined formula. (Hint: note that f appears in both formulas).

Name____________________________ Period_______

WS5.2

The Bohr Model of the Atom Prior to the work of Niels Bohr, it was known that electrons existed outside of the nucleus, but beyond that very little was known. 1. What was the observation that Bohr based his research on?

2. The Balmer formula is : Solve this formula for n = 4.

w

1 1   1 0.01097 2  2  n  2

3. The heart of Bohr’s discovery was that he was able to come up with real meaning to this formula. Draw a hydrogen atom with several energy levels (“shells”) around it and show electronic emission from the fourth shell to the second shell.

4. Draw diagrams indicating atomic emission and absorbance.

5. All of the visible atomic emissions for hydrogen enter the second energy level. What wavelength of light is emitted when an electron moves from the second energy level to the first energy level? What type of light is this?

Name:_______________________________________

Period:______

WS5.3

Electron Configuration (L1 only) Directions: Draw the electron configurations with orbital notation for each of the following atoms. Example: Here is the electron configuration of Sulfur with orbital notation. 16S:

1. Scandium:

1s2 2s2 2p2 3s2 3p4

2. Gallium:

3. Silver:

4. Krypton:

5. Iron:

6. Bromine:

7. Californium

8. Write the electron configuration using shorthand notation of the following elements: a. sodium

b. An oxygen anion, O-

c. Radon 9. Two substances that have the same number of electrons are isoelectronic. For example, both the fluorine anion F- and neon have ten electrons, they are isoelectronic. a. The bromine anion is isoelectronic with what uncharged element? b. Argon is isoelectronic with which monocation?

Name___________________________________ Period __________________

WS 5.4

Electron Configuration NOT! Worksheet (L1 only) In this unit we have seen how the electrons are organized around the nucleus. It is a very detailed view of the electrons location, and various rules to help keep it all straight have been devised, and are shown below. In each problem below, the electron configuration is incorrect. Fix it, and explain what law or principle (not Principal!) was violated. EXAMPLE: Law Violated: Aufbau Principle Fixed: 1. 1Hydrogen:

2s1

Principles and rules of electron configuration Principle or rule Heisenberg

Bad

Good

1s22p1

1s22s1

(e-position uncertain)

Aufbau (build up) Hundâ&#x20AC;&#x2122;s Rule (spread out) Pauli (opp. spins)

1s22s22p2 1s2

Unit 5 electrons Dr. B.â&#x20AC;&#x2122;s ChemAdventure

Law Violated: __________ Fixed:

2. 17Chlorine

3. 39Yttrium (next page)

1s2

2s2

2p6

3s2

3p5

1s2

2s2

2p6

3s2

3p6

4s2

3d10

4p6

5s2

4d10

1s22s22p2 1s2

Law Violated: __________ Fixed:

Laws Violated: __________ Fixed:

4. 8Oxygen 5.

1s2

2s2

2p4

106Seaborgium

1s2

2s2

2p6

Law Violated: __________ Fixed:

3s2

3p6

4s2

3d10

4p6

5s2

4d10

5p6

6s2

4f14

5d10

6p6

7s2

5f14

6d4

How to ace the Electrons Exam

Howtoaceitunit5

In this Unit our goal was to determine where the electrons are in atoms. To find out, we performed two experiments that revealed the sharp lines that excited pure elements produced. We then analyzed this data from a historical perspective, beginning with the work of Niels Bohr. For this we needed to review the properties of light, including frequency, wavelength, energy, and, common types. This involved the use of the speed of light equation (s = wf) and an understanding of the electromagnetic spectrum. We then showed how the key mathematical solutions of Balmer and Rydberg allowed Bohr to put it all together to postulate energy levels, where atomic emission explains light, and produces the spectral lines observed for all elements. This was followed by a detailed look at the electron around the nucleus. We found that not only do electrons reside in shells, there are also subshells or orbitals within each shell. We observed how they spread out within an orbital (Hundâ&#x20AC;&#x2122;s Rule), and even how they spin when near each other (the Pauli Principle). We learned the configurations of electrons for all elements following the Aufbau Order, and how to write it all down by electron position, configuration, or orbital notation. This can rapidly tell us how many electrons are in each shell and subshell, the spin of each electron, and the number of unpaired electrons. The limits of observation of the electron are a result of the Heisenberg Uncertainty Princliple, which states that it is impossible to measure the position and velocity of an electron simultaneously, due to the extreme sensitivity of the electron. Finally, we showed how valence is easy to determine using the periodic table, and that valence may be drawn using electron dot formulas, also known as Lewis Dot Formulas. During this study we found that the periodic table is well designed to show the number of valence electrons for any element. In our next unit we will apply this to our understanding of the periodic table. To dominate this test, review all of the material in his packet: The lessons, the labs, and the worksheets. Here is some of the key information you should know: To ace this exam you should know:

1. Draw the symbols for Democritus, Aristotle, Ghazali, Lavoisier, Dalton, Thomson, Rutherford, and Bohr 2. What is the significance of each symbol? Try to assign one or two key words for each symbol. 3. What are the dangerous wavelengths of light? 4. How does light relate to electrons? 5. What is wavelength? Units? 6. What is frequency? Units? 7. Rearrange the speed of light equation to show what frequency is equal to. 8. The electromagnetic spectrum: what is it? 9. Frequency: how does it relate to energy and safety? 10. Wavelength- how does it relate to frequency? 11. Energy: which rays have the highest energy? 12. Safety: why are radio waves generally considered safe? 13. Types of radiation Really long waves include ___________ and _______________; really short waves include __________ and ____________. The ___________________ (long/short) waves are dangerous. 14. Convert 452 nanometers to meters (107 nm = 1m) 15. Use s = wf to find the frequency of 452 nm light. 16. (Level one only) The Balmer formula. Find it in your notes: 17. Significance 18. Solve for the n= 3 to n = 2 transition: 19. Atomic Emission Spectra: How did we observe it? 20. Emission vs. absorbance- what is the difference? 21. The Bohr model of the atom- draw a model 21.5 What is the difference between electron configuration, and orbital notation?

22. Electron names to zirconium. For example, manganese has the symbol ____ 23. L1 only: Electron configurations- all elements…do iodine using noble gas notation. 24. L1 only: Orbital notation: all elements. Do silicon. Include the number of valence electrons, and the number of unpaired electrons. 25. The Heisenberg Uncertainty Principle. State what it is and why briefly. 26. L1 only: Orbitals: s, p, d, and f…how many electrons for each? How many orbitals for each? 27. L1 only: Aufbau principle. Give an example where it is broken, and fix it.

28. L1 only: Pauli exclusion principle. Break it and fix it.

29. L1 only: Hund’s Rule. Break it and fix it.

30. Lewis Dot Structures. Draw oxygen, for example

31. Valence Electrons. Do each column in the periodic table..

32. Why is it important to use scientific references, rather than websites, when writing a scientific paper?

33. Where are the electrons in an atom?

f. 6 pt 2009

The Periodic Table Unit 6 What is the periodic table good for?

Introduction

The universe is composed of approximately 120 elements. These are pure substances with a fixed number of protons: hydrogen has 1, helium 2, carbon 6 etc.

They could be listed in a few rows:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120

But that wouldn’t really tell us much. Or maybe they could be organized another way, since for example 5 x 4 x 3 x2 x 1 = 120… but would there be a reason for organizing it that way? If the universe only has about 120 elements, it seems reasonable to expect some sort of organization to them. That is what the periodic table is about: trying to figure out how the most basic matter in the universe is organized. But there’s a problem. The periodic table just doesn’t look right. Here it is below: An important concept in science is known as Occam’s Razor, which suggests that the simplest

answer tends to be the right one.

In the table on the left most rows and columns are

of different length, and it is in two pieces. This is not a simple table. Could it be that we humans just havenâ&#x20AC;&#x2122;t figured it out yet? Iâ&#x20AC;&#x2122;m hoping you can do better. Somebody should. 1s2

A Basic Idea for the Organization of Matter.

2s2 2p6

We learned in our last unit that the periodic table is organized based on electron configuration. A good idea. But

3s2 3p6

3d10

4p6 4d10

4f14

consider this:

4s2 5p6 5d10

5f14 5g18

On the right is an organizational layout of the periodic table

5s2 6s2 6p6 6d10

6f14 6g18

7s2 7p6

7d10 7f14

8s2 8p6

8d10

9s2 9p6

10s2

based only on electronic configuration, that looks much more symmetrical. Notice how it closely it resembles a triangle. Is this a better scheme for the elements? This basic design may be a fundamentally better way of creating a more symmetrical and informative periodic table. A periodic table based on this idea is shown on the following page. Other more creative periodic tables have been created, including spiral designs like the one below (my favorite).

While we look at how the elements are organized, give some thought to your own organizational scheme. Me, being German, I am looking for major organization and balance. Maybe your are comfortable with a more abstract pattern to the universe, like the one I found on the web shown at the bottom:

Keep your mind open to your own pattern to the elements as we study them, and keep in mind that nobody has yet created the perfect periodic tableâ&#x20AC;Śit is still a mystery waiting to be solved. - In our lab activity you will create your own pattern.

Three-Dimensional Periodic Tables lab6.1

50 points Elements are not two-dimensional, so why should the periodic table be? In the introduction to this unit, you saw several unusual versions of the periodic table. Your goal for this project is to create a useful three-dimensional version of the periodic table which shows a key property of the elements. Working in groups of 1 or 2, create a three-dimensional periodic table that highlights a key property of the elements. Choose one of the following properties: 1. Size: How big the atoms are (atomic radius). 2. Mass: How heavy the atoms are (atomic mass). 3. Radioactivity: How dangerous the atoms are: radioactivity (this will require some reading up) 4. Electronegativity: How electronegative the atoms are. 5. Appearance: The color of each element in itâ&#x20AC;&#x2122;s pure state at room temperature. 6. Hardness: How hard each element is (it may depend on its allotropic form) 7. Odor: What each element smells like (this is tougher than it sounds) 8. Toxicity: What happens when you eat each element? 9. Flammability: Which elements catch fire, and how easily 10. Price: How much do they cost? 11. Abundance: Which are the rarest elements on earth? 12. Location: Where on earth can each element be found naturally? 13. Usage: What is the most common end-use for each element 14. Rust resistance: Which elements oxidize, and how easily? 15. Biological Need: Which elements are necessary for survival, and in what quantities? 16. Military Value: Which elements have the highest strategic value for the military? 17. Universal Abundance: What is the abundance of each element in the universe (not just on earth) 18. Lunar or Martian Abundance: What is the abundance of each element on Mars or the Moon? 19. Choose your own topic and have it approved. Homework for Day 1: Complete Prelab on following page (note this is 40% total of your grade!). Data and materials. Find your data for each element online from a reputable source and complete the periodic table on the following page. Bring in any necessary materials to make a 3dimensional table (paper, tape, scissors provided- bring in something to make it 3-D like Styrofoam, legos, wood blocks, etc).

3-D Periodic Table Data: Prelab Note that this is 40% of your project grade Topic:_______________________________________________ Sources for data: (note that 20% of your grade is based on the reliability of your sources)

Materials brought in to make it 3-dimensional:

Data: Insert your data for each element below.

Your score will be based on 1. 10 Points: Sources: Prelab Source material is reliable and useful 2. 10 points: Preparation: Prelab is completed 3. 10 points: Functionality: the added dimension serves a useful purpose 4. 10 points: Neatness: The design is neat and orderly, with a polished, finished look. 5. Timeliness: Project is done on time.

Name: ______________________________________

Period: _____

WS6.1

Periodic Table WS I: History and organization 1. List three elements that were known for over 2000 years

2. Lavoisier was the first major contributor to the periodic table. What was his contribution?

3. What was the big breakthrough that led to the discovery of nearly 50 more elements, and who is credited with the discovery?

4. Around when did this take place?

5. What did John Newlands get right, and what did he get wrong?

6. What three elements did Mendeleev predict?

7. The least reactive group in the periodic table is the __________ __________ 8. Which group of metals desperately wants to lose an electron?

9. Which group easily loses 2 electrons?

10. This is the first element in the d-block.

Name: ___________________________________Period: _____

Periodic Table WS II: Groups, periods, and reactivity 1. List three alkali metals 2. List two alkaline earth metals 3. What key feature do the families (also known as columns or groups) of the periodic table have in common?

4. How many valence electrons do the halogens have? 5. True or false: The noble gases are grouped together because of their high reactivity. 6. True or false: The noble gases all have 8 valence electrons.

7. Columns in the periodic table are known as __________ or _____________; rows are called _____________. 8. Write the ionic compounds that would form when the following elements combine: Example: Sodium and chlorine: NaCl

Name: ____________________________________Period: _____

Using Periodic Trends to Predict Atomic Radius Directions: Using the trends discussed in class, answer each of the following questions as â&#x20AC;&#x153;logicallyâ&#x20AC;? as possible.

1. Which of the following kinds of atoms has the largest atomic radius? 31Gallium

11Sodium

19Potassium

2. Which of the previous kinds of atoms had the smallest atomic radius?

3. Rank the following three kinds of atoms by increasing atomic radius, highest = 1. 76Platinum

79Gold

47Silver

4. Rank the following three kinds of atoms by increasing atomic radius, highest = 1. 15Phosphorus

17Chlorine

35Bromine

5. Which of the following kinds of atoms has the largest atomic radius? 21Scandium

22Titanium

30Zinc

6. Which of the atoms in question 6 had the smallest atomic mass?

Name: ______________________________________

Date: ______

WS6.4 Period: _____

Using Periodic Trends to Predict Electronegativity Directions: Using the trends discussed in class, answer each of the following questions as â&#x20AC;&#x153;logicallyâ&#x20AC;? as possible. 0. What is electronegativity? 1. Which of the following kinds of atoms has greatest Electronegativity? 3Lithium

(Li)

11Sodium

(Na)

19Potassium

(K)

2. Which of the previous kinds of atoms had the lowest Electronegativity?

3. Rank the elements from highest (1) to lowest (3) electronegativity. 13Aluminum

14Silicon

17Chlorine

4. Rank the elements from highest (1) to lowest (3) electronegativity.. 34Selenium

17Chlorine

9Fluorine

5. Which of the following kinds of atoms has the greatest Electronegativity? 35Bromine

20Calcium

12Magnesium

6. Which of the atoms in the previous question had the lowest Electronegativity?

Name: ______________________________________

Date: ______

Using Periodic Trends to Predict Ionization Energy

1. Which of the following kinds of atoms has highest Ionization Energy?

3Lithium

19Potassium

37Rubidium

2. Which of the previous kinds of atoms had the lowest Ionization Energy?

3. Rank the following three kinds of atoms by increasing Ionization Energy. 9Fluorine

16Sulfur

17Chlorine

4. Rank the following three kinds of atoms by increasing Ionization Energy. 3Lithium

5Boron

6Carbon

5. Which of the following kinds of atoms has the greatest Ionization Energy? 7Nitrogen

15Phosphorus

51Antimony

6. Which of the previous kinds of atoms had the lowest Ionization Energy?

WS6.5 Period: _____

Name: ______________________________________

Date: ______

WS6.6 Period: _____

Using Periodic Trends to Predict Elemental Properties

1. Which of the following kinds of atoms has highest Ionization Energy? Fluorine (F) Francium (Fr) Cesium (Cs) 2. Which element wants electrons the most? Or, said another way, which element has the highest electronegativity? Oxygen (O) Sulfur (S) Selenium (Se) 3. Rank the following three kinds of atoms by increasing Ionization Energy: 1 = highest, 3 = lowest Fluorine (F) Sulfur (S) Chlorine (Cl) 4. Rank the following three kinds of atoms by increasing Ionization Energy. Lithium (Li) Sodium (Na) Potassium (K) 5. Which of the following kinds of atoms has the lowest Ionization Energy? Nitrogen (N) Oxygen (O) Carbon (C) 6. Which of the previous kinds of atoms had the lowest Ionization Energy? Cesium (Cs) Iron (Fe) Fluorine (F) 7. Which ionic compound has the highest melting point Cesium chloride (CsCl) cesium fluoride (CsF) cesium iodide (CsI) 8. Describe what electronegativity is using your own words.

9. Describe what atomic radius is using your own words.

10. Describe what ionic radius is using your own words.

How to Ace the Periodic Table Unit

Howtoaceunit6

To ace this quiz, review your notes, the Periodic Table PowerPoint, the worksheets, and the labs completed. Then, try the questions in this guide. Get help on anything you don’t understand, and finally, sleep well knowing you are in good shape. Know the history of the periodic table 1. List 3 elements known before 1790 2. Lavoisier: What was his contribution 3. Poor John Newlands: what did he get right, wrong 4. Mendeleev: Why is he “the father of the periodic table”? 5. Groups or families are ____________ 6. Periods are _________ 7. Metals, nonmetals, and metalloids: Where is the dividing line? Groups: For each below know where they are, ions formed, and why 8. Alkali metals 9. Alkaline Earth Metals 10. Halogens 11. Noble Gases 12. S,p,d, and F blocks- where they are, how many electrons in each 13. Lanthanides are the ____ column in the ___ block 14. Actinides are the ____ column in the ___ block 15. Valence electrons- know for each family 16.Know the number of valence electrons for charged and uncharged atoms. And be sure to know what elements the charged atoms are isoelectronic with. For example, Sc3+ is isolectronic with _______ The 4 Trends: 17. Atomic and ionic radii. Largest element/ion is___; Arrange Ca, Cs, Sr 18. Electronegativity and ionization energy: Highest value is for the element _______. Arrange Cl, Se, Te 16. Know how to draw simple ionic compounds based on charge. For example sodium chloride = NaCl 17.Magnesium chloride, potassium oxide 18. Aluminum fluoride, lithium sulfide 19. Be sure to know the names of elements 1-40. 20. Describe a useful 3D periodic table 21. What is the periodic table good for?

Answer

Be prepared to give a one paragraph answer Be prepared to give a one page answer.

Our Essential Question:

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stock value ď&#x20AC;˝

new price x investment original price

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Sodium

Beryllium

Magnesium

Potassium

Calcium

Rubidium

Strontium

Boron

Aluminum

fluoride

bromide

permanganate

bicarbonate

Chloride

hypochlorite

iodide

chlorite

Cesium

Barium

Francium

Radium

nitrite

perchlorate

Ammonium

Zinc

nitrate

bromate

silver

oxide

sulfide

chromate

dichromate

chlorate

bisulfate

hydroxide

cyanide

iodate

carbonate

sulfite

sulfate

nitride

phosphide

acetate

phosphate

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Mix 24 g Mg with 32 g S. Makes 56 g MgS.

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  

sulfur 32.07

1. Ice melts. What are the COOL signs of a chemical reaction you observed? Is it a chemical reaction? _____ How could you prove it? 2. Wood burns. What are the COOL signs of a chemical reaction you observed? Is it a chemical reaction? _____ How could you prove it?

3. Iron rusts. What are the COOL signs of a chemical reaction? Is it a chemical reaction? _____ How could you prove it?



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H O NaHCO3

H C C

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H baking soda _____ g _____ mol

acetic acid _____ g _____ mol

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H ethyl acetate

water

CO2 carbon dioxide

_____ g

_____ mol

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NO2 H

H O2N

NO2 H

T 

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10 grams H 2 x

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mole H 2 2 moles H 2 O x  5 moles H 2 O 2 grams H 2 2 moles H 2

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

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1 mole NaOH 40 g NaOH x x 0.1 liter solution ď&#x20AC;˝ 4 g NaOH liter solution mole NaOH

HO Greasy: will dissolve in greasy solvents

watery: will dissolve in watery solvents (like water)

A â&#x20AC;&#x153;brickâ&#x20AC;?: hard to dissolve in anything.

S1 S2  P1 P2

S1 S2 3.3 g /L 9.9 g/L (1 atm)(9.9 g/L)  ;  ; x=  3 atm P1 P2 1 atm x (3.3 g/L)

Percent solution by mass ď&#x20AC;˝

mass solute x 100 mass solution

Percent solution by volume ď&#x20AC;˝ moles of solute Liters of solution

volume solute x 100 volume solution

40 g NaCl 0.5 moles NaCl x x 0.08 Liters solution = 1.6 grams NaCl Liter of solution mole NaCl

Percent solution by mass ď&#x20AC;˝

Percent solution by volume ď&#x20AC;˝

mass solute x 100 mass solution

volume solute x 100 volume solution

moles of solute Liters of solution

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Chemistry 1. Intro 2. data 3. matter 4. the atom 5. electrons 6. periodic table 7. bonding 8. reactions 9. the mole 10. gases 11. solutions 12. Energy 13. Reaction rates 14. equilibrium 15. Acids and bases

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Title Name, Date

Data Q = mcDT Q= M= C= DT = =( )( )( ) = ___ J = ___Nutritional Calories

(For example: Potato Chip Calorimetry Or Energy Analysis of a common Snack Food) Schematic drawing With labels Of your calorimeter

caption

Conclusions Include the Nutritional Calories calculated for your chip, the estimated real nutritional calories for your chip, and an explanation for the difference.

Pick a topic: 1. What is calorimetry? 2. Sources of Error in our calorimeter design 3. A better design for the next experiment 10 points: 1. Effort: 5 points -does this represent 45 minutes of effort? 2. Calculations: 3 Points -are they accurate? 3. Analysis: 2 points: Why are the results so bad (or so good).



reaction rate 

Δconcentra tion Δtime

 Δconcentration reaction rate  Δtime



0.100mol / L  0.22mol / L 4s  0s

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collision theory



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↔



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         

Acids and Bases How do we explain, measure, and neutralize acids and bases?

Strong acids and bases are often powerful, dangerous substances. Sulfuric acid (H2SO4) will decompose sugar into black charcoal. Nitric acid (HNO3) reacts with many metals, and hydrochloric acid (HCl) will eat away at a penny from the inside out. The base sodium hydroxide (NaOH) will react with grease and even human hair, and

hydrofluoric acid (HF) cannot be stored in bottles since it reacts with glass. What makes these substances so reactive? What is the essential chemical unit of an acid or a base? We can find the answers to these questions by taking a close look at the most abundant chemical on earth, which also the most abundant chemical in our bodies: What is water? If you took a liter of absolutely pure water, you would find not one substance, but three. (Actually you would find more than that if you include isotopes, but that is another story). The major substance is H2O which we are all familiar with, and the other two are the essential chemical forms of acid and bases. These three exist in chemical equilibrium, which we just studied.

water In this unit we will take a close look at this equilibrium and how we can conveniently measure it: this is pH. We will perform a simple chemical assay to measure the exact acid or base composition of any aqueous substance: titration. Finally, we will find out what gives these substances such potent chemical reactivity. Schedule As we have done for each unit, you will begin with a discovery lab, the goal of which is to explore the properties of the acidic and basic substances that you encounter every day. We then will hear from the experts, and take a look at the conclusions they have drawn. By the end of this unit you will be able to 1. Recognize common acids and bases 2. Measure the acidity and basicity of any substance using several different methods 3. Understand what an acid or base is using 2 complementary definitions 4. Determine how pH is related to acid or base concentration (L1 only) 5. Precisely measure the acidity or basicity of any substance by titration. Lesson 1: Household acids and bases lab Lesson 2: What is water? pH and exponents Lesson 3: More acid/base math Lesson 4: Neutralization Lesson 5: Neutralization Lab Lesson 6 Review Lesson 7: Acid/base test

Data Table: Conclusions/Questions: 2. How can you tell?

1. Which of the household solutions tested are acids?

3. Order the substances tested by increasing pH. Lowest pH (most acidic) 0

Highest pH (most basic) 8

4. Using a crayon or markers, draw a color guide for measuring the ph of a substance using your juice indicators: Indicator juice 1: 0

Indicator juice 2: ______________________ 0

4. Can each juice indicator be used to determine the strength of acids and bases? Explain.

5. Which test method is superior overall? Why?

6. Based on your data, what are acids like in general?

6. Based on your data, what are bases like in general?

6. Is it possible for a substance to be neither acidic, basic, nor neutral pH? Give an example and explain.

Data Table: Household Acids and Bases

Introduction: Many common household solutions contain acids and bases. Acid-base indicators such as litmus paper or even red cabbage juice turn different colors in acidic and basic solutions. They can, therefore, be used to show if a solution is acidic or basic. An acid turns blue litmus paper red, and a base turns red litmus paper blue (remember Blue = Basic). The acidity of a solution can be expressed using the pH scale. Acidic solutions have pH values less than 7, basic solutions have pH values greater than 7, and neutral solutions have a pH value equal to 7. In this experiment, you will test the pH of various household substances using a pH meter, variable-range pH paper, litmus paper, and a selection of juices. Our goal is to evaluate the accuracy and precision of each technique.

Procedure: Obtain a few drops of each solution and evaluate the acidity or basicity of each substance using the techniques indicated. Watch carefully as your instructor demonstrates the method to use for each assay.

Data Table: Test Tube

Solution

Blue Litmus paper

Red Litmus paper

pH Paper

Indicator juice 1

(1-14)

_____________

pH meter

Draw the color please

2 3 4 5 6 7 8 9

Tap Water

______________ Draw the color please

(0.0-14.0)

Indicator juice 2

Phenol-phthalein solution

105 10 3



 



Name ___________________________________________

Period ____________

Percentage of acetic acid in vinegar by titration Introduction Vinegar is a mixture of acetic acid (C2H4O2) and water. Is it mostly water, or mostly acetic acid? In this experiment we will find the percent acetic acid in vinegar by mass. Since acetic acid is an acid, it will react with a base. The more base it takes to neutralize the acetic acid, the higher the concentration of acetic acid. This principle is known as titration: Assaying the concentration of an acid or base by neutralizing it. Procedure 1. Fill a buret with 1M NaOH and record the initial volume:____

2. Add exactly 25 mL of vinegar and 3 drops of phenolphthalein to a flask and place it under the buret. 3. Drip in the 1M NaOH while stirring until the solution just becomes permanently pink. Record the final volume:_____ Total NaOH added: ____ mL (trial 1) 4. Perform two more trials Total NaOH added: _____ mL (trial 2) Total NaOH added: _____ mL (trial 3) Average volume NaOH added:______________ mL 5. Calculate the Molarity of the vinegar using the titration formula:

Molarity of unknown =

molarity of known x liters of known liters of unknown

(This equation is true only when the known and unknown react on a equimolar basis, which is true in this case) For this experiment we can rewrite the formula

vinegar Molarity =

(NaOH Molarity)(NaOH volume) vinegar volume

The NaOH Molarity as well as the vinegar and NaOH volume can be found above in bold.

Molarity of vinegar = _______ M

6. Use the same technique to determine the molarity of a diluted vinegar solution that is at your table. List your procedure, perform your calculation, and show it all below.

Clean up and answer the questions below at your regular seats.

Questions 1. To calculate the percent acetic acid in the vinegar, we need to convert from grams to moles., where 60 grams of acetic acid (C2H4O2) is a mole. Here is a sample calculation starting from a 3 Molar acetic acid solution:

60 grams acetic acid 180 g acetic acid 3 moles acetic acid 1 liter solution x x = = 18% Liter solution 1 mole acetic acid 1000 grams solution 1000 g solution Use this sample calculation to determine the percent acetic acid in your vinegar by mass. Show your work below:

% CH3CO2H = _______ %

2. If it took 12 mL of 1M NaOH to neutralize 25 mL of vinegar, what is the percent acetic acid by mass, and what is the percent acetic acid of that vinegar solution? Show your calculations below.

Percent acetic acid:

Acids and Bases: Lab Practical ___ Points ___ Points Each group will be given an unknown acid or base. Our sample number is __________ Find out 2. The pH of the solution

1. If it is an acid or a base

3. The Molarity of the solution

Results: 1. To determine if our solution is acidic or basic, we used the following procedure:

This showed that our solution is a(n) acid/base (circle one) 2. To determine the pH of the solution we performed the following test(s):

This showed that the pH of our solution is____________ (please give your answer with three significant figures)

significant figures) 3. To determine the Molarity of the solution, we used the following procedure:

Final Results: We were given sample #_____, which is a(n) acid/base (circle one) with a pH of _____ and it is a ______M solution. This showed that we were given a _____M solution (please give your answer with three significant figures).

Final Results: We were given sample #_____, which is a(n) acid/base (circle one) with a pH of _____ and it is a ______M solution.

means it has both the components or an Arrhenius acid (H+) and an Arrhenius base (OH-). However, an aqueous solution of ammonia (NH3) has a pH of 13 and is definitely a base, but it doesn’t contain the hydroxide anion. Instead, it creates then hydroxide anion when it reacts with water; here is the ionization reaction:

This reaction has produced ammonium hydroxide (NH4OH); by showing the ions separately we can see what has happened. Ammonia has accepted a proton (H+). Ammonia is an example of a Bronsted-Lowry base: a substance that accepts a proton. A Bronsted-Lowry acid is a substance that donates a proton.

Acids & Bases

NH3 + H2O  NH4+ + OH-

ACID

BASE

Arrhenius

Look at the equilibrium reaction again. When bases accept protons they form conjugate acids: NH4+ is an example of a conjugate acid. When acids lose protons they form conjugate bases: OH- is an example of a conjugate base.

Summarize the two main acid-base theories in the table below.

BrønstedLowry

2. What is a conjugate base?

3. What is a conjugate acid?

Label the acid (A), base (B), conjugate acid (CA), and conjugate base (CB) in each of the following reactions.

Example:

HCl Acid

H2O  H3O+ base conj. acid

Clconj. base

4. H2SO4 + NH3  HSO4- + NH4+ ____ ___ ___ ___ 5. CH3CO2H + H2O  H3O+ + CH3CO2____ ___ ___ ___ 6. CH3NH2 + H2O  CH3NH3+ + OH____ ___ ___ ___ Give the conjugate base for each of the following Brønsted-Lowry acids. Examples: HSO4- SO42- (to form a conjugate base remove H+) HBr Br-

7. HI _______

8. NH4+ ________

9. H2CO3 _________

d. HNO3 ________

Name ___________________________ Period ___

ws15.3

Aqueous Acids and Bases â&#x20AC;&#x201C; Additional Topics

Please know the names, formulas, and common names of the following common acids and bases

Please know the names, formulas, and common names of the following common acids and bases: Also, be aware that there is a difference between a strong acid or base, and a concentrated acid or base. A strong acid or base ionizes completely in solution. These include for example hydrochloric acid, nitric acid, and sulfuric acid (H2SO4). Weak acids and bases such as acetic acid or citric acid hold on to their acidic proton more tightly- they only ionize partially in solution. If acids or bases they are diluted with a lot of water, however, they become dilute. As an arbitrary rule, we will consider any solution of an acid or base with a concentration greater than 1M to be a concentrated acid. Read this information carefully, then answer the questions below.

----1. What is this stuff? Write the chemical formula for each

NaOH ______ __________ 2. Write the formulas for Sulfuric acid: H2SO4 Nitric acid:___________ Acetic acid:________ Magnesium hydroxide:_________

________

_______

Chemistry: pH and pOH calculations II

ws15.4

We are mostly water. So is our planet. Most of our chemistry experiments use water. Thus, we should know what water is in detail. It’s H2O, right? Not quite. About one in every million molecules of water is ionic, existing as H+OH-, not the polar covalently bonded H-O-H. When we add bases like NaOH to water, the water has more OH- in it, and when we add acids like HCl the water has more H+ in it. A liter of pure water has 10-7 moles of H+ in it, and 10-7 moles of OH- in it. That’s 0.0000001 moles. A liter of battery acid, on the other hand, has 10-1 moles of H+, and 10-13 moles of OH- in it. That’s 0.1 moles, which is a million times as many moles of H+, and a million times fewer OH- moles. Someone came up with the bright idea of using the exponents, and “10-7 moles per liter hydrogen ion concentration” became simply known as pH 7, where pH means “powers of hydrogen” Since the log of 10-7 is -7, we are taking the negative log when we convert from concentration to pH: pH = -log [H+]. Note also that the more acidic something is, the less basic it is. In our example above, battery acid has a hydrogen ion concentration of 10-1 moles per liter, or a pH of 1: Battery acid (H2SO4): [H+] = 10-1M = pH 1

It also has a hydroxide ion concentration [OH-] of 10-13M, which is a pOH (“powers of hydroxide”) of 13: Battery acid (H2SO4): [OH-] = 10-13M = pH 13 The pH and the the pOH always add up to 14. This means that the H+ and OH- concentrations always can be multiplied to equal 10-14M pH + pOH = 14 [H+][OH-] = 10-14

We can summarize the relationship between concentration and pH:

Making sense of this for the first time can take time. The examples on the next page will enable you to master these concepts.

e the details provided below for the first row to help fill in the table. Part 1: Fill in the missing information in the table below.

[H+][OH-] = 10-14 Enter 10^-14/1.66E-4

pH 3.78 [H+]

10-pH

Enter 10^-3.78

[H+]

pOH

[OH-]

Acid or base? Example

1.66 x 10-4

10.22

6.0 x 10-11

Acid Orange juice

pH>7 = base pH<7 = acid

pH + pOH = 14 Enter 14-3.78

Use the change sign (-) button, not the subtract button

in the missing information in the table below. pH 1.

[H+]

pOH

3.78

3.89 x 10–4 M

5.19

4. 5.

4.88 x 10–6 M 8.46

8.45 x 10–13 M

2.14

8. 9. 10. 11. 12.

[]

2.31 x 10–11 M 10.91 7.49 x 10–6 M 9.94 2.57 x 10-8

ACID or BASE? Example

Part 2: For each of the problems below, assume 100% dissociation. 1.

Write the equation for the dissociation of hydrochloric acid.

Find the pH of a 0.00476 M hydrochloric acid solution.

Write the equation for the dissociation of sulfuric acid.

B. 3.

Find the pH of a solution that contains 3.25 g of H2SO4 dissolved in 2.75 liters of solution.

A. B.

Write the equation for the dissociation of sodium hydroxide. Find the pH of a 0.000841 M solution of sodium hydroxide.

Write the equation for the dissociation of aluminum hydroxide.

If the pH is 9.85, what is the concentration of the aluminum hydroxide solution?

Write the equation for the dissociation of calcium hydroxide.

If the pH is 11.64 and you have 2.55 L of solution, how many grams of calcium hydroxide are in the solution?

Directions: Answer each of the questions below with the correct reaction, volume or molarity for either the acid or base in question. Use the solved examples as a guide.

Titrations Directions: Answer each of the questions below with the correct reaction, volume or molarity for either the acid or base in question. Use the solved examples as a guide.

Fill in the missing products or reactants: Example: CsOH + HBr  CsBr + H2O 1. HCl + _______  KCl + H2O 2. 2HF + Mg(OH)2  _________ + ___________ 3. NH3 + HNO3  _____________ Example: What is the molarity of a CsOH solution if 30.0 mL of the solution is neutralized by 26.4 mL of 0.250 M HBr solution?

Solution:

2. What is the molarity of a HCl solution if 43.33 mL 0.100 M KOH solution is needed to neutralize 20.00 mL of unknown solution? 3. What is the concentration of a household ammonia cleaning solution if 49.90 mL of 0.5900M HCl is required to neutralize 25.00 mL of the ammonia solution?

4. In a titration, 33.21 mL 0.3040 M Rubidium Hydroxide solution is required to neutralize 20.00 mL HF solution. What is the molarity of the Hydrofluoric Acid solution?

5. A 35.00 mL sample of NaOH solution is titrated to an endpoint by 14.76 mL 0.4122 M HBr solution. What is the molarity of the NaOH solution?

Titration: challenge problems 1. 49 mL of 0.200 M HCl is mixed with 50 mL of 0.200 M NaOH to reach the endpoint. a. moles HCl = b. moles NaOH = c. [H+] d. [OH-] e. pOH = 2. 86.30 mL of an HCl solution f. pH = was required to neutralize 31.75 mL of 0.150 M NaOH. Determine the molarity of the HCl.

3. 63.15 mL of calcium hydroxide is required to titrate 18.9 mL of a 0.200 M H3PO4 solution. What is the molarity of the basic solution?

4. How many mL of 0.160 M HClO4 are needed to titrate 35.0 mL of 0.215 M LiOH? 5. 25.0 mL of 1.00 M HCl are required to titrate a Drano solution (active ingredient NaOH). How many moles of NaOH are present in the solution?

6. Ten grams of vinegar (dilute acetic acid, HC2H3O2), is titrated with 65.40 mL of 0.150 M NaOH. a. What is the Molarity of the vinegar solution? b. How many grams of acetic acid are present in a one liter of the vinegar solution?

c. How many grams of acetic acid are present in 10 grams of the vinegar solution d. How many molecules of acetic acid are present in 10 grams of the vinegar solution?

The Secrets behind the “Water into Wine” Demonstration Worksheet WS15.7 We recently saw the water into wine demonstration, where Water (colorless)  Wine (pink)  Martini (colorless) champagne (fizzy)  milk (cloudy)  margarita (opaque pink) To do this we hid small amounts of colorless chemicals in the original water decanter, as well as the individual glasses:

1. Water: The water contained a few drops of phenolphthalein, a colorless liquid acid, which we can draw as

henolphthalein-H 2. Wine:asThe wine do glass has athe Bronsted-Lowy definintion of an acid). So the where H is the acidic proton that it will donate, all acids (recall few drops of dilute NaOH in water glass (which doesn’t contain anything) is colorless. it: a strong base. Write the resulting acid-base reaction (Hint: it is a double replacement reaction, and acids donate protons): Phenolphthalein-H + NaOH  __________________+________________ The sodium salt of phenolphthalein (which you just drew above) is a vivid pink substance- hence the rose wine. Thus phenolphthalein solutions are colorless in acidic pH, and pink when basic. This makes them useful as indicators, much like pH paper. 3. Martini: A martini is colorless. How can we make our pink phenolphthalein solution colorless? (Hint: reacting it with base made it pink). Answer:___________________________________ For this we use sulfuric acid. Write out the products for this double replacement reaction: (Hint: remember what acids do). Phenolphthalein-Na+ + H2SO4  _______ + ____________ We are back to normal phenolphthalein, a colorless martini-looking liquid. 4. Champagne: Since we are back to an acidic solution (we used excess sulfuric acid), we can generate some fizz by reacting it with baking soda. Please fill in the intermediate and final products: H2SO4 + NaHCO3  _________ + _________  CO2(g) + _____________

5. Milk: Our milk glass contains some barium nitrate. Balance and write the products for this double replacement reaction (hint: SO4 is a 2- anion, NO3 is a 1anion): ____Na2SO4 + ____BaNO3  ______________ + _____________ 6. Strawberry Margarita: Finally, we hide excess strong base in the margarita glass. We’ve got all kinds of stuff in there now, but colorwise the phenolphthalein will dominate. Write out the reaction again between phenolphthalein and sodium hydroxide to form our hot pink and this time still opaque solution:

_______________ + ________________  ______________ + ____________

And that’s the science behind the magic.

How to ace the acid-base test In this unit we explored the properties of acids and bases. We started by getting a feel for acids and bases by checking the pH of a number of household chemicals. We found that bases tend to be slippery, and acids tend to be sour or bitter. We explained this by exploring the Arrhenius Model for acids, where H+ and OH- are the acidic and basic components of an acidic solution.

We then looked at these solutiomns quantitatively by examining the pH scale of acids and bases. We observed that the ion concentrations in water are quite low, and that the equilibrium constant Kw of water is 1 x 10-14 moles per liter. We learned how to convert acid or base concentration to pH and the reverse as well. Finally, we all learned a technique for precisely measuring the pH of any solution: titration.

To ace the acids and bases exam review all labs, worksheets, slides and notes. And pay particular attention to the guided questions on the following pages.

1. Know your â&#x20AC;&#x2DC;vocabâ&#x20AC;&#x2122;; remember for this exam you are required to know the names and formulas of the following common acids and bases:

1. What is an acid?

12. pH

2. What is a base?

13. pOH

3. Hydrochloric acid

14. Titration

4. Hydrobromic acid

15. Phenolphthalein

5. Nitric acid

16. Indicator

6. Sulfuric acid

17. Neutralization

7. Acetic acid 8. Sodium hydroxide 9. Calcium hydroxide 10. Hydroxide ion 11. Hydrogen cation

. Know how to use your formulas (They will be provided on the exam; be able to know how to use them) Kw = [H+][OH-] = 10-14 pH + pOH = 14 titration: [unknown] = (volume kwnn)(molarity known)/(volume unknown) 18. Example: For pH 3 solution [H+] = _____, [OH-] = _____, pOH =____, the solution is Acidic/basic. 19. Example: For pH = _____ [H+] = _____, [OH-] = _____, pOH = 2 19.5 (L1 only) For pH = _____ [H+] = _____, [OH-] = _____, pOH = 2.3 -Be able to determine the concentration of an acid or base when titrated with a standard solution. 20. Example : Write a procedure for titrating an unknown aqueous substance.

21. Example . 323 mL of 2.1M NaOH were required to neutralize 414 mL of an unknown acid. The H+ concentration of the acid must be _______ M.

22. Example .

33 mL of 0.1M LiOH were required to neutralize 14 mL of an unknown acid. The [OH-]

concentration of the acid must be _______ M

Use your knowledge of stoichiometry to determine how many molecules of acid or base are in a solution. 23 (l1 only). Example: How many molecules of NaOH are in 3 liters of a 2M NaOH solution?.

24(l1 only).. Example: How many molecules of NaOH are in 3 liters of a pH 13.2 solution?

25 (l1 only). Example: How many hydroxide ions are in 17 liters of a 0.42M Al(OH)3 solution?

Be prepared to answer the essential question for this unit: How do we explain, measure, and neutralize acids and bases? Extra credit Research the molecular basis of phenolphthalein…why does it change color at a specific pH…how does

the molecule change structure, and why does that result in a color change?

-Be able to determine the concentration of an acid or base when titrated with a standard solution.

Example 8: Write a procedure for Example 9. 323 mL of titrating an unknown 2.1M NaOH were acid. required to neutralize 414 mL of an unknown acid. The [OH-] concentration of the acid must be _______ M.

f. Polyprotic acids (honors only)

-Know the chemical formulas of sulfuric, carbonic, nitric, and boricExample acid 10: Please give the formulas for the following acids: Sulfuric__________

-Be able to write the complete equilibrium 11: Write reactions for theseExample polyprotic acids in water the three lines that show the complete aqueous equilibria for phosphoric acid. 1.