Solutions by ChemistryAdventure

3. How does it happen?

Solutions What are they? Homogeneous mixtures Only one thing visible

Everywhere!

What is in a solution?

Solute(s):

Solvent: dissolver

1. Where are they? 3. How does it happen?

Where are they?

mouthwash

dissolved

Is it a solution?

yes

water

granite

bronze

yes

Chemadventure Chapter 11: Solutions

4. How does it NOT happen?

5. Will heating or pressure help?

6. Make Crystals

A molecular view of dissolving:

7. Types 8. Measuring

Fully dissolved salt water

Partly dissolved

Solvation:

= solvent surrounding the solute

Electrolyte: Salt. Non-Electrolyte:

Not a salt (ex: sugar) Chemadventure Chapter 11: Solutions

9. Making them 10. Using them

2. What are they?

6. Make Crystals

9. Making them 10. Using them

1. Where are they?

5. Will heating or pressure help?

7. Types 8. Measuring

2. What are they?

4. How does it NOT happen?

Solubility

2. What are they?

Ethanol

CH3CH2OH

yes

Propanol

CH3CH2CH2OH

Yes

Butanol

CH3CH2CH2CH2OH

No!

Rule of thumb:

watery “like dissolves like”

Chemadventure Chapter 11: Solutions

4. How does it NOT happen?

5. Will heating or pressure help?

6. Make Crystals

Heating Solutions A solubility surprise:

Heating makes Most solids More Soluble Most gases Less Soluble

Global implications

4 Chemadventure Chapter 11: Solutions

9. Making them 10. Using them

2. What are they?

Greasy

7. Types 8. Measuring

3. How does it happen?

yes

9. Making them 10. Using them

CH3OH

1. Where are they?

Name

Greasier

Why don’t oil and water mix? Soluble in Formula water?

Methanol

1. Where are they?

6. Make Crystals 7. Types 8. Measuring

3. How does it happen?

5. Will heating or pressure help?

4. How does it NOT happen?

3. How does it happen?

2. What are they? 1. Where are they? 3. How does it happen?

Is there a way to increase the solubility of ANY solution?

Yes: Henryâ&#x20AC;&#x2122;s Law

Solubility is proportional to pressure

S~P

S1/P1 = S2/P2

If sol. Is 1g/L at 1 atm, it will be 2 ______g/L at 2 atm Everyone: if solubility is 3.45 g/L at 5.6 atm, what is the solubility at 1 atm? 3.45/5.61 = S2/1

S2 = 0.614 g/L

(Henrys Law Worksheet)

5 Chemadventure Chapter 11: Solutions

4. How does it NOT happen?

5. Will heating or pressure help?

6. Make Crystals

How to make crystals:

Watch a video online here or play the flv file here or the avi file here

The process:

The principle:

recrystallization supersaturation

and cool

Or evaporate Or Reduce pressure

The process of forming the very first crystal during crystallization is called

nucleation

Fun nucleation video here Chemadventure Chapter 11: Solutions

9. Making them 10. Using them

1. Make a hot supersaturated solution

saturated

7. Types 8. Measuring

2. What are they?

6. Make Crystals

9. Making them 10. Using them

1. Where are they?

5. Will heating or pressure help?

7. Types 8. Measuring

4. How does it NOT happen?

3. How does it happen?

2. What are they? 1. Where are they?

Solutions Type Gas-gas Gas-liquid Liq-Liq Solid-liq Solid-solid

Ex. Air Soda Vinegar Ocean Fillings

Solvent N2 H2O H2O H2O Ag

solute O2 CO2

Acetic acid

salts Hg 7

Chemadventure Chapter 11: Solutions

4. How does it NOT happen?

5. Will heating or pressure help?

Concentration

10 g NaCl 90 g H2O

% by mass (% m/m) 10% NaCl by Mass

58.5 g NaCl 1L solution

Molarity (M) 1M NaCl

Mass solute x 100 Mass of solution Volume of solute x 100 Volume of solution Moles of solute Liter of solution

58.5 g NaCl 1 kg water

Molality (M) 1m NaCl L1 only

Moles of solute Kg of solvent

58.5 g NaCl 162 g H2O

Mole Fraction (X)

Moles of solute

XNaCl = 0.1

L1 only

Moles solution

Chemadventure Chapter 11: Solutions

9. Making them 10. Using them

10 mL juice % by volume (% v/v) 90 mL H2O 10% NaCl by Volume

6. Make Crystals 7. Types 8. Measuring

3. How does it happen?

6. Make Crystals

9. Making them 10. Using them

2. What are they?

5. Will heating or pressure help?

7. Types 8. Measuring

1. Where are they?

4. How does it NOT happen?

3. How does it happen?

2. What are they? 1. Where are they?

• You have a 100.5 mL solution containing 5.1 g glucose (molar mass = 180.16 g/mol). What is the molarity of that solution? • Solution • Molarity = moles of solute/L of solution • Moles solute = 5.1 g glucose x 1 mole glucose/180.16 g glucose = 0.0283 moles glucose • L of solution = 100.5 mL x 1L/1000 mL = 0.1005 L solution • Molarity = 0.0283 moles/0.1005 L solution = 0.282M Molarity ws 9 Chemadventure Chapter 11: Solutions

4. How does it NOT happen?

5. Will heating or pressure help?

Another example

6. Make Crystals

• Make 100 mL of a 1M NaOH solution

Take 4 g NaOH; add water til 100 mL.

10 Chemadventure Chapter 11: Solutions

9. Making them 10. Using them

1 mole NaOH 40 g NaOH x x 0.1 liter solution  4 g NaOH liter solution mole NaOH

7. Types 8. Measuring

3. How does it happen?

Molarity Examples

6. Make Crystals

9. Making them 10. Using them

2. What are they?

5. Will heating or pressure help?

7. Types 8. Measuring

1. Where are they?

4. How does it NOT happen?

3. How does it happen?

2. What are they? 1. Where are they?

6. Make Crystals

• As solvent increases, concentration

decreases

• C1 V1 = C2 V2

• Concentration may be Molarity, % v/v, % mass • How can I dilute 53.4 mL of a 1.50M soln of NaCl to make it a 0.800M solution? • Easy: C1V1 = C2V2 • (1.50mol/L)(53.4mL)= (0.800mol/L)(V2) • V2 = 100. mL • (dilute to 100 mL to get 100 mL of a 0.8M soln)

Chemadventure Chapter 11: Solutions

4. How does it NOT happen?

5. Will heating or pressure help?

Colligative Properties

6. Make Crystals 7. Types 8. Measuring

3. How does it happen?

5. Will heating or pressure help?

9. Making them 10. Using them

L2: concepts only. (L1 all)

• How do solutes affect boiling and freezing point?

collective

Solutes elevate the boiling point Solutes lower the freezing point (road salt) 12 Chemadventure Chapter 11: Solutions

9. Making them 10. Using them

2. What are they?

Dilution

7. Types 8. Measuring

1. Where are they?

4. How does it NOT happen?

3. How does it happen?

Fewer solvent molecules on surface

L1 only

“Particle molality” # of ions

BP elevation constant molality

Sugar = 1 NaCl = 2 CaCl2 = 3

= moles solute/Kg solvent What is the boiling point of a 2.75m aqueous NaCl solution?

1. Where are they? 3. How does it happen?

Tb =Kbm x pm Particle molality = 2 (easy to forget) • = (0.512)(2.75 x 2)= 10.22 oC • BP = 102.82 oC

Chemadventure Chapter 11: Solutions

4. How does it NOT happen?

5. Will heating or pressure help?

6. Make Crystals

Solutes lower freezing point

Interfere with crystal formation L1 only “Particle molality” Tf = Kfm

Sugar = 1 NaCl = 2 CaCl2 = 3

constant molality = moles solute/Kg solvent What is the freezing point of a 2.75m aqueous NaCl solution?

Tf =Kfm x pm Particle molality = 2 (easy to forget) • = (1.86)(2.75 x 2)= 10.22 oC • FP = -10.22 oC 14 Next: Energy

Chemadventure Chapter 11: Solutions

9. Making them 10. Using them

FP depression

7. Types 8. Measuring

2. What are they?

6. Make Crystals

9. Making them 10. Using them

1. Where are they?

5. Will heating or pressure help?

7. Types 8. Measuring

2. What are they?

Solutes elevate boiling point

4. How does it NOT happen?

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)

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