Global Thinkers: Physics and Chemistry 3. Secondary (demo)

s c i s y h P y

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12 M ON

THS LICEN CE

DIGITAL PROJECT

INCLUDED

3

GLO BAL

THINKERS

Conntoewnledtgse in the course Basic k

CHALLENGES THAT LEAVE THEIR MARK

Organize a space room ....................................................................10

Scientific knowledge

........................................................................................................12

The use of science 1. What is science?

2. Physics and chemistry 3. Physical magnitudes. Unit and measurements 4. Measuring instruments. Errors 5. Multiples and submultiples 6. The language of science 7. Laboratory equipment. Safety rules Understand, reflect and put your skills to the test

1 Matter. Gases

....................................................................................................................... 30

Learning about gases 1. The states of aggregation 2. The kinetic-molecular theory 3. State changes 4. Ideal gas laws 5. The Earth's atmosphere Research project The energy of the atmosphere Practical work Evidence of atmospheric pressure Understand, reflect and put your skills to the test

2 Solutions

........................................................................................................................................ 50

Water, universal solvent 1. Substances, mixtures and material systems 2. Solutions, suspensions and colloids 3. Concentration of a solution 4. Solubility 5. Water. Characteristics and contamination Research project Drinking bottled water Practical work Concentration and density of a solution Understand, reflect and put your skills to the test

Portfolio ....................................................................................................................................................... 70

CHALLENGES THAT LEAVE THEIR MARK

I become an influencer.................................................................... 72

2

3 The atom

......................................................................................................................................... 74

Scientific theory and paradigm shifts 1. First ideas about the atom 2. From the electrical nature of matter to the first atomic model 3. From radioactivity to the nuclear model of the atom 4. The nucleus of the atom 5. Classification of chemical elements 6. Atomic orbitals 7. Applications of radioactive isotope ions Research project Radioactive waste Practical work The chemistry of fireworks Understand, reflect and put your skills to the test

4 Chemical substances

............................................................................................ 96

The food industry 1. Simple and compound substances 2. Atoms bond 3. Chemical bond 4. Molecules and crystals 5. Chemical formulas 6. Biomedical and technological industrial applications Research project Fertilizers and explosives Practical work Simple substances and compounds Understand, reflect and put your skills to the test Appendix Chemical formulation and nomenclature

5 Chemical reactions

................................................................................................. 130

Chemistry and global warming 1. Changes in the composition of substances 2. Atomic theory of chemical reactions 3. Chemical equations 4. Laws of chemical combination and chemical equations 5. Amount of substance 6. Chemistry, environment and society Research project CO2 sinks Practical work Chemical reactions with gaseous substances Understand, reflect and put your skills to the test

Portfolio. .................................................................................................................................................... 150 CHALLENGES THAT LEAVE THEIR MARK

Photographic exhibition: The all-seeing eye..........................152

6 Forces and their effects

.............................................................................. 154

Understanding the forces of nature 1. Forces 2. Deformations 3. Motion 4. Everyday forces 5. Newton's Laws 6. Simple machines Research project The acceleration of gravity Practical work Elastic deformations Understand, reflect and put your skills to the test

7 The nature of forces

9 Energy sources

.............................................................................................................. 226

Electric cars 1. Rational usage of energy 2. Power plants 3. Transport and distribution of electrical energy 4. Electrical energy and power 5. Electric power in homes Researchn project Types of lamps Practical work Energy for cooking Understand, reflect and put your skills to the test

Portfolio .............................................................................................246 Glossary .............................................................................................248

............................................................................................ 180

Geolocation 1. Gravitational force 2. Electrostatic force 3. Magnetic force 4. Electromagnetism Research project Magnetic force of an electromagnet Practical work Where is north?

Understand, reflect and put your skills to the test

Portfolio ............................................................................................ 200 CHALLENGES THAT LEAVE THEIR MARK

Collective wisdom.......................................................................... 202

8 Circuits

........................................................................................................................................... 204

The transistor 1. Electric current 2. Electrical circuit 3. Ohm's law 4. Kirchhoff's Laws 5. Electric devices 6. Electronics Research project Evolution of microprocessors Practical work Resistance measurement Understand, reflect and put your skills to the test

3

4

S E C N A T S B U S L A C CHEMI

The food industry The characteristics of the matter that surrounds us depend on the properties of each substance. The variety of these is infinite, from those that conduct electricity or heat, to those that are so strong that it is almost impossible to modify them. During the past centuries, humans have learned to enhance some characteristics of substances to obtain more specific functions.

One specific case of this kind of change is the food industry. To get to your table, food goes through an industrial process that commences when agricultural products are ready for distribution. 98% of industrialized countries process the food that they cultivate, while only 30% of developing countries manage to process their food.

Apart from bridging the gap between industrialized and developing countries in this regard, the food industry faces another problem: the chemicals used in its production and the waste it generates.

96 96

READING AND LISTENING Fertilizers and pesticides add nutrients and control pests accordingly, but they also pollute soils and rivers. Furthermore, deforestation, which results from the land that is needed to grow crops, contributes about 20% of greenhouse gas emissions.

1 Define the following: 1

Food industry

2 To bridge the gap 3 Deforestation

2 What kind of nutrients do fertilizers provide to the soil?

3 Summarise the paragraph in one or two sentences.

4 What problems do the use of fertilizers and pesticides have on the health of soils and ecosystems? Look for some measures that can be taken to restore degraded land.

GES THAT

CHALLEN

EIR MARK

LEAVE TH

WHAT ARE YOU GOING TO DISCOVER? In this unit The food industry

LEARNING SEQUENCE

1 Simple substances and compounds 2 Atoms bond 3 Chemical bond 4 Molecules and crystals 5 Chemical formulas 6 Industrial, biomedical and technological

applications Science workshop

VIDEO. THE OCTET RULE. 4.1 Create a YouTube channel, with private access, where you will upload the videos you create.

4.2 Following the best practice model you developed, create a video explaining the ways in which elements can achieve the nearest noble gas electron configuration. In this unit, the videos will be simple and short.

You can choose to view a presentation while listening to the presenter's voice.

Research project: Fertilizers and explosives

You must do each of the presentations in a group and the steps to follow can be:

Practical work: compounds

• Make a scheme.

Simple

substances

and

At anayaeducacion.es To motivate you:

• Video: "Before you start".

• Documents: "Do you want to dedicate yourself to environmental engineering?", "Do you want to dedicate yourself to microbiology?"

"Do you want to dedicate yourself to be a chemist/specialist in femtochemistry?".

For the previous detection of ideas:

• Interactive activity: "Initial self-assessment".

• Presentation: "What you need to know".

To study

• Video: "Carbon nanotubes".

• Simulation: "Build a molecule".

• Presentation: "The periodic table".

• Molecule viewer: Molecular substances, ionic crystals, metallic crystals and covalent crystals.

• Presentation: "To study".

To evaluate yourself:

• Interactive activity: "Final self-assessment".

• Solutions to numerical activities.

And, in addition, all the necessary documentation to apply the project keys.

• Enter the texts. They should be short and direct.

• Search for the images or animations to be added, checking that they have the relevant licenses.

• Perform animations and transitions.

• Make a script of the audio and rehearse it.

• Choose ambient music, with the appropriate license.

It is convenient that for this first video you opt for a simple option without much audiovisual material.

VIDEO. THE CHEMICAL BOND. 5.1 Make a video to explain the different ways in which atoms come together to form compounds. Use a molecular modeling program to generate images to illustrate your explanations.

VIDEO. THE MOLECULAR MASS. 6.1 Explain in a video how the molecular mass of a compound of industrial interest is calculated. You can include an explanation about the importance of that compound, the production process, etc. + for guidelines, go to anayaeducacion.es

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1

SIMPLE SUBSTANCES AND COMPOUNDS

1.1 The bricks of matter We have studied that matter is made up of atoms, and the different types of atoms are ordered according to their atomic number in the periodic table of elements. Many of these chemical elements have been known since Ancient Times and others were discovered once chemistry was fully developed as a science. But how was it possible to discover different types of atoms before even knowing they existed?

To answer this, we must turn to a classification of the substances based on their composition and determine whether it is possible to break down the substance or not:

• Simple substances, if the units that make them up are formed by atoms of the same kind. Therefore, this type of substance is not broken down into any other simpler substance.

• Compounds, if they are formed by the bonding of atoms of different chemical elements. Compounds can be broken down into simple substances; for example, water can be broken down into dioxygen and dihydrogen.

Identify elemental entities Look at the lower-left image, in which each sphere represents an atom. What would you say is the elementary entity that forms each of the substances?

Return to this question once you have finished the unit.

1.2 Natural and artificial elements In general, we can affirm that chemical elements whose atomic number is less than or equal to that of uranium (Z = 92) correspond to atoms found in the Earth’s crust forming simple or compound substances. Their discovery necessarily took place by isolating the simple substances formed by each one of them.

The remaining known chemical elements have been obtained by the radioactive decay of others or in particle accelerators. Their discovery has not involved isolating the simple substance, but rather directly observing the atom.

Simple substance or compound Pure substance

2

Can it be broken down into other substances by chemical processes?

5

115

113 Yes

No

26

Fe

44

Nh Co Ni 28

27

NIHONIUM

46

45

29

Cu

47

77

108

109

Os

Compound

Simple substance

Both compounds and simple substances are formed by units which are identical to each other. The difference is that compounds are formed by two or more different atoms.

98

Hs

Ir

Mt

13

Al

McGa

30

Zn

31

MOSCOVIUM

C

7

N

14

15

32

33

Si

Ge

117 P

8

O

16

9

F

17

S 118 Cl

52

53

86

118

83

84

85

114

115

116

117

79

80

110

111

112

113

Au Hg

Tl

Ds Rg Cn Uut

Pb

Sb Bi

Te

Po

36

OGANESSON

82

78

Ar

Ts Br OgKr

As Se TENNESSINE

51

Sn

Ne

18

35

50

In

10

34

49

81

Pt

6

48

Ru Rh Pd Ag Cd

76

B

He

I

At

54

Xe

Rn

Fl Uup Lv Uus Uuo

The new chemical elements discovered in recent Look years already have a name and symbol. up information on the names of the new chemical elements. What criteria is set for naming them?

UNIT

4

1.3 Chemical elements and simple substances It is important to bear in mind that the name “element” can either refer to the type of atom with the same number of protons (in other words, with the same atomic number), or the simple substance formed by atoms of this type. To avoid confusion, many times in this book we will use the term “chemical element” to name the type of atoms and not the simple substance. For example, iron (simple substance) is formed by atoms of the chemical element iron.

1.4 Large groups in the periodic table

Analyze the hydrogen group

HH

GEN

HYDRO

In addition to grouping chemical elements into families or groups, and in periods, and according to certain properties, we can classify the chemical elements into:

• Metals. The majority of chemical elements (those shown in blue in the image below) are metals. Metal atoms lose electrons easily and, therefore, form cations.

What group does hydrogen belong to? Does it present the same properties as metals?

• Nonmetals. In contrast to what its name may seem, the chemical elements called “nonmetals” do not include all those which are nonmetals. Rather, this name is only used for the ten elements shown in yellow. These atoms form anions.

• Semimetals. The simple substances formed by these chemical elements share certain properties with metals, but also present properties of non-metallic substances. These are the chemical elements shown in green in the table below.

• Noble gases. These are the elements of group 18 of the periodic table. The substances made up of these chemical elements are gaseous and are formed by atoms which are not bonded to each other. These characteristics allow to explain the charge of the ions and the form in which the other chemical elements are bonded to each other.

Understand, think, search...

Groups of elements in the periodic table Semimetals

Noble gases

Metals

1 Explain the difference between a

Nonmetals He

H

simple substance and a chemical element. Give an example of each one.

Be

B

C

N

O

F

Ne

Na Mg

Al

Si

P

S

Cl

Ar

Ga Ge

As

Se

Br

Kr

the periodic table of chemical elements have?

Ru Rh Pd Ag Cd

In

Sn

Sb

Te

I

Xe

3 Indicate whether the following

Rn

Li

K

Ca

Sc

Ti

V

Cr Mn Fe

Rb

Sr

Y

Zr

Nb Mo Tc

Cs

Ba La

Hf

Ta

Re Os

Ir

Pt

Au Hg

Tl

Pb

Bi

Po

At

Fr

Ra Ac

Rf

Db Sg Bh Hs

Mt

Ds Rg Cn

Nh

Fl

Mc

Lv

Ts

W

Co

Ni

Cu

Zn

2 How many rows and columns does

chemical elements nonmetals, noble semimetals:

are metals, gases or

a) Phosphorus, chlorine and carbon.

Lanthanides

Ce

Pr

Actinides

Th

Pa

Nd Pm Sm Eu Gd Td U

Np Pu Am Cm Bk

Dy Ho Cf

Er

Tm Yb

Lu

Es Fm Md No

Lr

b) Magnesium, calcium and zinc. c) Argon, xenon and radon. d) Boron, silicon and germanium.

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2

ATOMS BOND

2.1 The chemical bond A chemical bond is the result of the force of attraction that bonds two atoms together.

Simple substances, such as dichlorine, Cl2, and compound substances, such as ammonia, NH3, are made up of microscopic particles and are the result of the bonding between atoms, a bonding which is called a chemical bond and which is produced because bonded atoms are more stable than isolated atoms, except in the case of noble gases, which we will see later.

2.2 Noble gases and the octet rule If the atoms of noble gases do not bond it is because they are stable despite being isolated. Observing the characteristics of these atoms we can conclude that their stability comes from the number of electrons of its last shell:

• Helium (Z = 2), the first noble gas, has two electrons in its last shell.

As this shell is the only one it has, it will be full.

• The other noble gases have eight electrons in their last shell, but not all have their last level full. Of all of them, only neon has its last shell of electrons complete.

Draw conclusions Explain the different colour used to illustrate the electrons of the noble gases in the image.

From neon onwards, the noble gases do not have their last shell full due to how shells are completed, which will be studied in more advanced courses.

Electron configuration of the noble gases

2

He

HELIUM

10

Ne NEON

Helium and neon have their last shell of electrons full: however, argon and krypton do not have this shell full, even though they do have eight electrons in it.

100

18

Ar

ARGON

36

Kr

KRYPTON

In later years you will see that this is a first approach to the octet rule. This is the rule that predicts the formation of the bonding between atoms.

UNIT

4

The previous observations are summarised in the octet rule:

Atoms bond with each other so that, as a result of the bonding, they accommodate eight electrons in their last shell, except H, Li and Be which are left with two electrons.

An atom may acquire the electron configuration of a noble gas when it bonds with another atom, which means that as a result of this bonding the atom will have as many electrons as a noble gas. Ions are also formed to have the same number of electrons as a noble gas.

Investigate the types of chemical bond

2.3 Ways to achieve noble gas configuration When we studied the atomic orbital, we saw that a neutral atom can lose or gain electrons, giving rise to an ion. The number of electrons that it loses or gains is not random, but the number needed for its last shell to have the same electrons as the closest noble gas (two in the case of helium and eight for the other noble gases).

Three different types of chemical bonds are obtained from these two ways of achieving eight electrons in the valence shell: covalent, ionic and metallic.

But there are atoms which are very far from a stable configuration, so they would have to lose or gain an excessive number of electrons.

In these cases two or more atoms share electrons with each other, in order to obey the octet rule.

Research the types of chemical bonds and assign each one of them to the appropriate part of the diagram.

Ways of achieving eight electrons Atoms spontaneously acquire stability

can be stable like those of

Noble gases which have

losing electrons

gaining electrons

Cations

Anions

sharing electrons

to acquire Eight electrons in their last shell

Understand, think, search...

4 Make a diagram of the atom orbital for the first three periods of group 17 of the periodic table.

What conclusions do you draw?

5

Helium balloons float in the air, as this gas is less dense than the mixture of gases that form the air. Do you think it is advisable to throw helium balloons in an event on the environment? Explain.

6

“Noble gases […] are normally found in nature in isolation as their ability to react with other elements and form compounds is very limited. But it is still possible and a good number of molecules formed by noble gases has been studied in the lab”.

Agencia SINC, December 2013.

Look up the origin of this information and analyse it.

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3

CHEMICAL BOND

3.1 Electric charges of ions By means of the octet rule we can prove that ions of certain chemical elements have a determined electric charge. For example, aluminium forms cations Al3+; barium, Ba2+; chlorine, anions Cl–, and sulphur, S2–.

This is the case because, in this way, these elements achieve a stable electron configuration.

We can find out the charge of the ion by applying these steps:

• We deduce the number of electrons in the last shell from the group of the periodic table.

• By finding out the number of electrons of the last shell, we will know how many electrons it needs to gain or lose in order to have the same as the closest noble gas and, with this, the charge of the ion that is formed.

3.2 Ionic bond An ionic bond is the result of the force of attraction between cations and anions as their respective charges have opposite signs.

We have seen, in previous years, that one of the ways in which matter acquires electric charge is by means of exchange of electrons between the atoms that form it. Therefore, for an anion to be formed, a cation must be formed simultaneously, hence an exchange of electrons take place between both.

When this exchange has happened, there are two ions of opposite charges, which gives rise to electrical attraction between both.

Later, we will see that the ionic bond is not produced in two isolated ions, rather among a large number of them.

Charge of ions based on their position in the periodic table 1 1

2

H

2

HYDROGEN

3

Li

LITHIUM

11

Na

8

BERYLLIUM

OXYGEN

MAGNESIUM

3 21

POTASSIUM

CALCIUM

SCANDIUM

37

38

39

RUBIDIUM

STRONTIUM

K

Rb

Ca

Sr

O

16

Mg 20

19

9

4

Be

12

SODIUM

16

Sc

Y

YTRIUM

17

F

FLUORINE

S

SULFUR

34

Se

SELENIUM

52

Te

TELLURIUM

17

Cl

CHLORINE

35

Br

BROMINE

53

I

IODINE

18

HELLIUM

Group

Lose or gain

Charge of the ion

Ne

No. of valence electrons

1

1

Lose

+1

2

2

Lose

+2

13

3

Lose

+3

16

6

Gain

-2

17

7

Gain

-1

He

10

NEON

18

Ar

ARGON

36

Kr

KRYPTON

54

Xe

XENON

The elements of the groups closest to group 18 (noble gases) lose or gain a number of electrons which is the same as or lower than four, forming ions. In this way they manage to have the same number of electrons as the closest noble gas. So, fluorine will gain an electron, forming F–, and magnesium will lose two, giving rise to Mg2+.

102

You can use what is shown here to find out the charge of the ions of the elements from the groups of this table.

For the remaining elements of the periodic table, since there are also elements that form ions, the reduction of the charge is not as simple, as you will see in later years.

UNIT

3.3 Bonding of atoms sharing electrons Some atoms are bonded together with others sharing electrons with each other, which can give rise to two totally different types of bonds: the covalent bond and the metallic bond.

The substances that present a covalent bond have very different physical and chemical properties to those of substances with a metallic bond.

• Covalent bond. This is the bonding between two atoms of elements from the nonmetal group, which may be of the same chemical element or of different chemical elements; which share pairs of electrons.

4

Problems solved

1. Indicate what type of ion will form beryllium,

based on the information on its location in the periodic system. What noble gas does the electron shell of the ion formed correspond to?

Beryllium is in the second group and second period, therefore its valence shell is the second and it has two electrons. It will form a cation Be2+ by losing these two electrons and it will have the same distribution of electrons in its orbital as helium.

2. Using the method that we have learned to

explain the charge of ions, indicate what type of ion forms hydrogen.

The electrons that they share belong to both atoms at the same time, as they are attracted by each one of the nuclei of the two bonded atoms. This type of bonding is very stable, and is therefore very difficult to separate.

Hydrogen has one electron in its valence shell, so it can:

• Metallic bond. This is the bonding of atoms of the same

– Lose an electron and be without electrons, forming H+. This hydrogen ion is also known as a proton.

metal as a result of all of them collectively sharing some of their electrons.

– Gain an electron and its orbital will be like that of helium, forming H–.

Structure of the covalent bond and the metallic bond

Water, H2O, is formed by one oxygen atom which is bonded to two hydrogen atoms, sharing a pair of electrons with each one of them.

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

The metallic bond is based on the attraction of each one of the charged atoms of the network with the electrons that they lose to the group.

Understand, think, search...

7 Deduce what charge the ions of the following elements

8 Indicate if it is possible for the following pairs of

will have, referring them to the closest noble gas in the periodic table: a) Chlorine. b) Potassium. c) Boron.

atoms to form a bond, according to the charge of their ions:

d) Oxygen.

a) Chlorine and fluorine.

b) Sodium and lithium.

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4

MOLECULES AND CRYSTALS

The microscopic particles that make up substances can be individual atoms or groups of two or more atoms. The term microscopic is used because these entities represent the smallest possible portion of a substance, whether it is simple or compound. The microscopic particles formed by several atoms may be molecules or crystals.

4.1 Molecules A molecule is a microscopic particle formed by atoms bonded with each other by means of covalent bond.

The majority of substances are formed by molecules. These microscopic particles are the result of the bonding of atoms of nonmetallic elements sharing electrons, in other words, they are the result of covalent bonds.

The atoms that form a molecule may be of the same or of different chemical elements. The number of atoms that make up a certain molecule is not variable, rather all molecules of one substance have the same number and type of atoms.

Interpret molecular models In the molecular models, the bonding between atoms is represented by sticks and the atoms by spheres.

How many atoms does a glucose molecule have? How many atoms is each nitrogen (blue sphere) bonded to in an ammonia molecule?

There are very simple molecules, such as dichlorine, ozone and water; others slightly more complex, such as fatty acids or glucose, and molecules with considerably complex structures, such as proteins, which function in the organism is determined by its three-dimensional structure.

4.2 Crystals A crystal is a three-dimensional structure and the units that form it keep a regular order.

In the solid state, particles have a three-dimensional structure. This structure is called crystal.

There are solids that are not formed by crystals, which are called amorphous solids.

Models to represent molecules

Ammonia molecules.

104

Water molecules.

Glucose molecules.

UNIT Crystals are classified according to the elementary entity that is repeated in their structure.

4

Types of crystal

There are three types: ionic, metallic or covalent crystals.

• Ionic crystals are formed by cations and anions which are bonded as a result of the attraction of electric charges of the opposite sign; in other words, as a result of ionic bonds.

• Metallic crystals are formed by atoms of the same metal, which share their electrons.

The electrons of the metallic network move freely through this network, more or less easily based on the metallic element.

• Covalent crystals are the result of the bonding of atoms of non-metallic elements by means of covalent bond.

This is why electrons in these networks do not move freely.

Anions (green) and cations (violet) of common salt (NaCl) bond to form an ionic crystal.

This variety of bonds between the atoms that form each type of crystal results in properties which are very different from each other.

• Ionic crystal substances, called salts, are fragile and soluble in water, like sodium chloride.

• Metallic crystal substances, called metals, are conductors of electricity, flexible, ductile and malleable. These are simple substances such as iron.

• Covalent solids, which is what covalent crystal substances are called, are hard, do not conduct electricity and are very stable. One example is the diamond.

Understand, think, search...

9

In metals, electrons are shared collectively, and have freedom of movement.

Make a diagram to connect the information of the bonding between atoms with the type of elementary entities that the substances may have.

10 Explain the differences between an ionic crystal, a metallic crystal and a covalent crystal.

11

From what you have studied, suggest a method for identifying the different types of crystal.

12

I see, I think, I ask myself. Research the kind of material used to build the top sector of a thermosolar power station for the generation of electric current.

13

Look up information on the fourth type of crystal which is not mentioned in this text, the molecular crystal, and explain how it is made up, as well as some of its characteristics.

The diamond is a covalent network solid made up of carbon atoms. It is the second most stable form of carbon.

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5

CHEMICAL FORMULAS

5.1 Chemical formulas From the common name of a substance, for example ammonia, without any additional information, it is not possible for us to know whether it is a simple substance or a compound. However, if we have the chemical formula we will be able to deduce what type of substance it is.

Chemical nomenclature

Simple substances

Look at the nomenclature annex to familiarize yourself with the way of writing chemical formulas and naming the substances.

Compound

Formula

Name

Formula

Name

Fe

Iron

Al2O3

Aluminium oxide

Cl2

Dichlorine

NH3

Ammonia

In the case of the simple substance formed by chlorine, its name may be dichlorine, therefore providing information on the subscript of the formula, or simply chlorine. In this last case we may confuse the name of the substance with the name of the chemical element that forms it.

5.2 Interpretation of chemical formulas Chemical formulas offer two kinds of information:

• Qualitative, as they indicate the chemical elements and the number of atoms that form the microscopic particles of the substance.

• Quantitative, through the subscripts of each chemical symbol. If the subscripted value is“1”, this is not written.

Interpretation of a chemical formula Number of chemical symbols One

Type of elements that make it up Simple substance

Metal

Nonmetal Chemical formula

Various

Compound

Metal + Nonmetal

Nonmetal + Nonmetal

106

Example Crystal

Al

Covalent crystal

C

Molecule

Cl2

Crystal

Molecule

Explanation

Subscript 1 (which is not written) indicates that this is the only element in the crystal.

Subscript indicates the number of atoms that forms each molecule.

Al2O3

Subscripts indicate the proportion of each ion in the crystal.

CH4

The subscripts indicate the number of atoms of each element present in the molecule.

UNIT

5.3 Molecular mass and mass of the formula unit

4

Butane molecule

The properties of a chemical substance are determined by those of the microscopic particle that makes them up. One of these characteristics is molecular mass or mass of the formula unit.

Molecular mass of a substance is the name given to the mass of its molecule, which is obtained from its chemical formula, adding up the atomic masses of the atoms that make up said molecule.

m (CH4) = 1 · m (C) + 4 · m (H)

In the case of simple molecular substances, molecular mass takes into account the number of atoms that form the molecule.

Barium fluoride crystal

In substances formed by crystals, the mass of its microscopic particle is called formula unit mass.

The formula unit mass of a pure substance is the sum of the masses of the atoms that are shown in the formula of the substance.

In order to quantify the mass of a unit of a substance formed by crystals, for example barium fluoride, BaF2, which is an ionic crystal, we use the formula of the compound. So, the formula unit mass is the mass of one atom of barium, Ba, and two of fluorine, F.

m (BaF2) = m (Ba) + 2 · m (F)

Problems solved

4. Calculate the formula unit of aluminium oxide based on the following information: an aluminium oxide crystal contains two aluminium atoms for every three oxygen atoms; m (Al) = 27 u, m (O) = 16 u.

5. Calculate the molecular mass of oxygenated water

(H2O2). Will it be higher or lower than the molecular mass of water?

The molecular mass will be:

The formula of the compound is: Al2O3.

The mass of the formula unit will be: m (Al2O3) = 2 · m (Al) + 3 · m (O) Replacing: m (Al2O3) = 2 · 27 u + 3 · 16 u = 102 u

m (H2O2) = 2 · m (H) + 2 · m (O) Based on the values of atomic mass of the periodic table: m (H2O2) = 2 · 1.008 u + 2 · 15.999 u = 34.014 u This value is higher than the molecular mass of water, which has one atom less in its molecule.

Understand, think, search...

14 Calculate the molecular mass of substances with

16 Indicate whether the following substances are

formulas: a) SO3, b) N2O3, c) FeS, d) Na2O. Is it right to talk of molecular mass in all of these cases?

Why?

formed by molecules or crystals. Calculate the

Sodium hypochlorite is used as a disinfectant agent in the purification of water. Look up the chemical formula of this compound and calculate the mass of its formula unit.

a) Barium oxide.

d) Ammonia.

b) Zinc hydride.

e) Barium chloride.

c) Arsine.

f) Aluminium oxide.

15

formula unit or molecular mass. Use the information from the formulae annex for this:

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6

INDUSTRIAL, BIOMEDICAL AND TECHNOLOGICAL APPLICATIONS

A number of simple or compound chemical substances are used as a basis for the manufacturing of products with high added value.

Some of the areas of research in chemistry consist of the design of new substances, or the discovery of new uses in known substances.

Depending on the field of use or application of the chemical substances, we can name industrial, biomedical and technological applications.

6.1 Industrial applications The most relevant chemical compounds in the industry are used, in turn, as raw material for other products, with the following standing out among them:

• Sulphuric acid (H2SO4). This is the most produced chemical compound in the world. The production of this acid is considered an indicator of the industrial capacity of a country, as it is used as a raw material for the manufacturing of other products. The majority of production of sulphuric acid is allocated to make fertilizers.

• Ammonia (NH3). The manufacturing process of ammonia from hydrogen and nitrogen in its day brought about a big revolution, as fertilizers were able to be obtained artificially and this process did not depend on natural sources. Fertilizers are substances of natural or artificial origin which have nutrients that can be absorbed by plants.

• Hydrochloric acid (HCl). Hydrochloric acid is used in sewage treatment processes, in food production and in the manufacturing of other chemical products. It is also used to remove oxide and impurities from steel before it is processed.

6.2 Biomedical applications Biomedicine comprises the sciences that study the development of new drugs, or active ingredients, and the understanding at a molecular level of the mechanisms that cause illnesses. The two objectives of biomedicine are closely related, as finding out the interactions between molecules in illnesses is the starting point for developing new drugs, or proposing new applications for the active ingredients that already exist.

Production of sulphuric acid Production of sulphuric acid in the EEC Italy 9 % Finland 9 % Greece 4 % Norway 4 %

Belgium and Luxembourg 12 % United Kingdom 18 % Germany 17 % France 12 %

Spain 15 %

Sweden 4 %

The Netherlands 6 %

The most industrialized countries are the biggest producers of sulphuric acid.

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The industrial processes of obtaining sulphuric acid require largely complex installations.

UNIT

4

Advances in biomedicine

It has recently been discovered that magnesium may be involved in the resistance that some bacteria present against certain antibiotics.

The development of nanoparticles which are capable of making drugs reach the inside of tumours is a promising aspect of research in biomedicine.

The action of quinoline on red blood cells affected by malaria is one of the latest discoveries in biomedicine.

6.3 Technological applications The design of new materials with electronic applications has allowed for an exponential advance in technology over recent decades.

Semiconductors, such as silicon, and materials such as graphene have had a large part to play in this development. In recent years, research on many materials with promising applications has taken up a notable space in the innovation and development of chemistry.

New materials +

+

+

+

+

+

+

+

+

– –

–

– –

Graphene is a material formed by a layer of carbon atoms with a number of applications; such as graphene nanocircuits.

–

–

–

– –

Antimonene, a new two-dimensional material of monatomic thickness made up of antimony atoms, shows promising properties in the storing of energy.

Understand, think, search...

17

Look up the hazard pictogram of the substances that are named on the previous page and list the hazards of handling them.

18

The mirror. Look up information on antimonene and graphene and list the similarities between these materials and the advantages of one against the other.

19

The field of biochemistry is very closely related to fields such as medicine and pharmacology, and

teams of experts from other areas work together making use of the latest technologies.

To reach the professional field of biochemistry, you can opt for education cycles in the chemistry family, or a wide variety of university degrees related to sciences and health sciences.

Name three professions that combine chemistry with another field of knowledge.

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P O H S K R O W E C N E I SC Research project

Fertilizer explosives Fertilizers are natural or synthetic substances which are added to the arable land in order to enrich it in one, or various, of the three elements needed for the life of plants: nitrogen, phosphorus and potassium.

Until the 20th century, nitrogen fertilizers of natural origin were used: guano (from Peru) and saltpetre (sodium nitrate from deposits in Chile, marketed with the name Chilean nitrate).

In 1913, German chemists Fritz Haber and Carl Bosch managed to fix nitrogen from the atmosphere (N2) in the form of ammonia (NH3) developing a very important industrial process, known as the BoschHaber process of ammonia synthesis.

Later, this process was used to synthesise fertilizers in the rest of the world, which drastically changed the worldwide capacity of agricultural production in the 20th century.

Objective Anomalous growth of algae resulting from eutrophication.

Carry out documentary research on the repercussions of using synthetic fertilizers

Procedure Puzzles Organise the class into small work groups and look up the following subjects on the Internet:

• Eutrophication, to achieve goal 6.3 of the SDG. • Organic agriculture and access to food, following goal 2.3 of the SDG. • The effects of intensive agriculture on the environment, in order to achieve the sustainable management and efficient use of natural resources (goal 12.2 of the SDG).

• The life of Fritz Haber and the controversy with his Nobel Prize for Chemistry.

FInal reflection 1 All discoveries have a beneficial application for society and some controversy. Finding out both allows us to have a critical view about their use and applications.

List pros and cons of the use of synthetic fertilizers in agriculture.

2 The problems that affect the whole society worldwide concern all of us who are part of it. As a future responsible citizen, draw up a list with your conclusions in this work.

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Results From the information you have found make some boards for the classroom which connect the related topics to the Millennium Goals of this project.

Decide among all of you the structure of these boards and the medium you are going to use to make them.

Discussion, conclusions and presenting your work Organise an exhibition and round table with another class group to show your work and use it as a basis for critical discussion.

Write up minutes from the round table which include conclusions and commitments.

UNIT

Practical work

4

Simple substances and compounds Approaching the problem When we mix iron and sulphur we get a heterogeneous mixture.

However, if we heat this mixture, do we get a new substance?

How can we know if this is a new substance?

Your proposal Remember any property of sulphur and iron which allows you to identify them and think how to check if new substances are obtained when you heat the mixture.

Our proposal

In your laboratory report, you can attach a photograph of each elementary substance, of their mixture and of the compound obtained in the experiment.

One characteristic of iron is that it can be attracted by a magnet.

This property will allow us to differentiate between iron in an elementary state and a compound in which iron is present.

Materials • Sulphur • Iron shavings • Two beakers • Watch glass • Crucible • Spatula • Bunsen burner • Steel rod • Magnet • Gloves for handling hot elements • Safety goggles Additionally, hydrochloric acid and test tubes

Guidelines Draw conclusions...

1 Do the final chemical mixture and compound have the same properties? Explain the experimental evidence you have found.

2 Describe what has happened in the crucible from two points of view: observation and the application of models seen in the unit.

3 The substance that has been formed in the crucible is iron monosulphide. a) Write its chemical formula. b) Is it a molecular substance or is it a crystal? Interpret the meaning of its chemical formula.

• In order to form the compound formed by iron and sulphur, you must heat the mixture using a metal rod which has been previously heated. Use protective gloves for hot elements and safety goggles, and take all necessary precautions.

• When you have obtained the chemical compound, it will be at a high temperature. Considerer enough time in your planning for the compound to cool down.

• Place two spatulas of sulphur and one of iron shavings in a beaker, mix them with a glass rod and label it as “mixture”.

• Prepare the same mixture as in the previous point, but this time in the crucible. Heat the metal rod on the flame of the Bunsen burner (using the safety elements) and then place the rod in the crucible.

Observe the phenomena that take place and write down the results in your notebook.

• Carry out the experiments that you have suggested to differentiate between the mixture and the compound. Write the experimental approach beforehand and ask your teacher about any additional experiment that can be carried out 111

S THAT

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1 Add the following concepts to the diagram

2

below: simple substances and compounds.

Make another concept map in which you summarise all the content of the unit.

Atoms can

gain stability by

Ionic bond

give rise to

Losing/gaining electrons

Sharing electrons

forming

forming

Metallic bond

Atoms of the same chemical element

made up of

Elementary entities

Atoms of a different chemical element

which may be

Covalent bond

Molecules that make up

? ................................

Crystals

that make up

? ................................

The solutions for all the numerical activities can be found at anayaeducacion.es

Simple substances and compounds 1 Look up information on the formula for the

and explain why:

following substances: methane, ethane, propane and butane.

a) Metals are good conductors of electricity, but poor conductors of heat.

a) Are they simple substances or compounds?

b) Metals tend to form cations, gaining electrons.

b) Could they be broken down into simpler substances?

c) Metals are brittle and brittle.

2 The name of some chemical elements makes reference to a scientist, therefore honoring him or her. For example, meitnerium is called this way in honor of Lisa Meitner, co-discoverer of nuclear fission. Investigate who is honored with the name of the chemical elements of atomic numbers 104, 107, 96, 99, and look up a reference on their contribution to science.

112

3 Indicate if the following sentences are true or false

d) Wires and sheets can be made of metals.

4 Look up the name and the year of discovery of the elements of atomic numbers 113, 115, 117 and 118.

5 Classify the following elements into metals, nonmetals, semimetals and noble gases: sodium, calcium, silver, argon, nitrogen, helium, phosphorus and silicon.

Remember to choose resources from this unit for your portfolio.

6 Indicate if these chemical elements are natural or artificial and write their chemical symbol: scandium, ruthenium, americium, lawrencium, lawrencium and wolfram.

Atoms bond 7 What are the only elements that are found in nature as isolated atoms? What group of the periodic table do they belong to?

8 Indicate if the following sentences are true or false: a) All gas atoms, without exception, have their last shell full. b) Each helium atom can accommodate up to six electrons more in its outermost shell. c) All noble gas atoms have eight electrons in their last shell.

9 Indicate the two mechanisms according to which atoms can bond. How many electrons must be in their last shell for the chemical species to be stable? What is this rule called?

10 Remember the shell model that we have studied for the structure of the atomic orbital and draw up a table with the number that corresponds to each shell, the letter that is used to name it and the maximum number of electrons that each one can accommodate.

14 Indicate if the diagram of the atomic orbital in the image can belong to a noble gas, a cation or an anion. In the case of ions, point out their corresponding chemical element:

16 Hydrogen can form a cation or an anion. Deduce the charge for each one of them and explain its stability.

17 Indicate if the following sentences are true or false and explain why: a) The bonding between a carbon atom and a hydrogen atom corresponds to an ionic bond. b) In a metallic bond, electrons are not associated with any pair of atoms. c) Atoms of different metallic elements can bond with each other. d) Calcium can form anions or cations, gaining or losing two electrons interchangeably.

18 Complete the table in your notebook.

No. of electrons per shell

b) Sulfur and oxygen.

F(Z =9)

c) Magnesium and oxygen.

K(Z =19)

f) Hydrogen and sodium.

Chemical-bond 12 Based on the octet rule, indicate the charge of the stable ions of these chemical elements: beryllium, calcium, sodium and sulphur.

13 How many electrons does an ion Li+ (atomic number of lithium 3) have in its last shell? Does it fail to observe the octet rule? Explain your answer.

K

L

M

N

Ion which will be formed

2

8

7

–

Cl–

Element

Cl (Z = 17)

e) Carbon and oxygen.

–

e) Ca2+. f) O2-. g) Al2+. h)S2–.

a) Li-. b) Cl3+. c) B-. d) Ar2+.

a) Sodium and fluorine.

d) Sulfur and calcium.

+

15 Indicate if the following ions are stable or not:

11 Indicate if the following pairs of chemical elements can be bonded sharing electrons or as a result of one of them losing electrons and the other gaining electrons.

–

Mg (Z = 12) B (Z = 5) Or (Z = 8)

19 Is it possible for an ionic bond to be formed between two atoms? What if this is a covalent bond?

20 Indicate which of the following ions have the same electrons as a noble gas and write the name of the noble gas. a) Li+.

c) Al3+.

e)S2–.

b) Na+.

d) K+.

f)N3–.

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c) The maximum number of microscopic particles in a crystal is 1023.

21 According to these characteristics indicate which

d) The maximum number of microscopic particles of a crystal depends on the compound it is.

type of substance is: a) Solid, soluble in water electricity in liquid state.

which

conducts

e) In a metallic crystalline network electrons move freely.

b) Crystalline network not soluble in water and not conductive of electricity. c) Solid that conducts electricity. d) Monatomic gas.

22 Indicate if the following sentences are true or false and explain why:

f) Ionic crystals have a net electric charge other than zero.

26 Explain why metals conduct electricity but why, however, ionic crystals and covalent crystals do not.

27 Explain the meaning of the chemical formulas for these ionic compounds:

a) A molecule is formed by an indeterminate number of atoms. b) In molecules, each atom bonds to the others by sharing its electrons with the rest of the atoms of the molecules. c) Molecules can have a maximum of ten atoms. d) In a molecule each atom is bonded to one or several atoms. Electrons are shared between pairs of atoms.

a)

c) CaF2.

b) KI.

d) Na2O.

28 Explain what keeps the elementary units of each type of crystal bonded.

29

23 Write the chemical formulas of the following compounds taking into account that the color red is for oxygen, black for carbon, white for hydrogen and yellow for sulphur.

a) MgCl2.

Check the crystal structure of silicon oxide (SiO2) in the molecule viewer that we offer you at anayaeducacion.es. Explain why in the chemical formula of this compound a subscribe one corresponds to silicon and two to oxygen.

Chemical formulas 30 Classify the following substances into the headings of the table, copying it into your notebook.

c)

Formula H2O

b)

d)

Type of substance

Types of elements

Compound Nonmetal-Nonmetal

Elementary entity Molecule

Fe2O3 CaO HCl Na2S N2

24 Indicate how many bondings there are between atoms in the molecules of the previous exercise.

Are these bondings the result of losing or gaining electrons, or sharing them?

25 Indicate if the following sentences are true or false: a) A crystal is an ordered structure formed by atoms. b) Compounds with crystalline structures tend to be solids in environmental conditions.

114

NH3 C2H6 CCl4 CO2 C3H8 NaCl

31 Explain the difference between molecular mass and formula unit. Give an example of a substance for molecular mass and another example of a substance for formula unit.

32 From the data on average atomic masses, calculate the molecular mass of these substances: a) H2.

b) CH4.

c) NH3.

d) C2H6O.

b) What are the symptoms of this disease? c) What type of treatment does it require? d) What are the forms of prevention of malaria?

Element

Atomic mass

Hydrogen

1.01 u

e) What role do pesticides play in the spread of this disease?

Carbon

12.01 u

37 One of the classic treatments of malaria is

Oxygen

16.00 u

Nitrogen

14.01 u

quinoline, whose mechanism has been recently uncovered. Based on the figure:

33 Connect each one of the formulas from the previous exercise with the representation of its molecule and indicate if these are simple substances or compounds: a)

b)

c)

a) Write the formula of this compound, given that black stands for carbon, white for hydrogen and blue for nitrogen.

d)

b) Indicate how many bondings there are between atoms and what type of bond this is. c) Is quinoline a molecule or a crystal?

34 Calculate the formula unit of the following: a) K2S.

b) BaS.

c) BaCl2.

d) KCl.

To do this use the average atomic masses of the period table from the textbook.

Industrial, biomedical and technological applications 35 One of the substances represented in activity 23 appears in the different transformations that make up the synthesis process of sulfuric acid; indicate which one it is and what environmental effects it has.

36

REFLECT In this unit you will have created a secure channel to start uploading the videos you have made based on already-known content and that you will have presented in a simple way, respecting the rules established in our protocol.

Reflect on your learning by filling out the questionnaire available at anayaeducacion.es.

Aspects

I understand and could explain it to my colleagues

I don't quite I do not understand it. get it I have some doubts

I do not know

We created a specific YouTube channel configuring it to have private access but to which all the members of the group had access. ...

Malaria is a disease caused by a parasite which is transmitted by a bite from an infected anopheles mosquito. The disease attacks structures which are essential for the functioning of the organism. Research this disease which represents a major health problem in many tropical and subtropical countries. Based on the heading of the activity and on the video on goal 3.3 of the SDG, answer the questions.

TEST YOUR SKILLS

a) Which structure of the organism is harmed by malaria?

Carry out the competency assessment included in anayaeducacion.es 115

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