Physics and chemistry 4ºESO Dualfocus Andalucía

dual FOCUS

DEMO

PHYSICS AND CHEMISTRY

4 SECONDARY EDUCATION www.anayaeducacion.es

SUMA

piezaS 1

2

3

Suma Piezas is an educational project by Anaya for Secondary Education.

The following people have worked on this book: CONTENT: Francisco Javier Pérez Cáceres (adaptation of the material from the book Física y Química 4º ESO) Editorial team: Manuel Gil, Margarita Marcos, María Ferrond and Sergio Gutiérrez Design, technical drawings and maps: Patricia G. Serrano, Juan Carlos Quignon, Rafael Sombría, Julio Vázquez, Miguel Ángel Díaz-Rullo and Miguel Ángel Castillejos Illustrations: Francisco Javier Pérez Cáceres, María Carmen Fuente and Pablo Vázquez Layout: Elvira López Rojo Translation: Mariano Guirao Photographs: Age Fotostock, Alamy/Cordon Press; Archivo Anaya (Candel, C.; Cosano, P.; Estrada-Nora, R.; Hernández Moya, B.; Martin, J.; Martín, J.A.; Ortega, Á.; Ortiz, J.; Osuna, J.; Peñuela Py, E.; Sánchez, J.; Torres, O.), Dreamstime/Quick images, Getty Images, iStock/Getty Images, NASA, NASA/ESA, 123RF and collaborators.

Commitment to Sustainable Development Goals Our publications contain carefully selected content, illustrations and language to comply with nondiscrimination on the grounds of gender, culture or opinion.

Grupo Anaya considers social and environmental responsibility to be one of its fundamental values.

For this reason, we are committed to: · continually improving our contents and materials related to the environment. · reducing our carbon emissions. · using natural resources responsibly. · making sure that our activity has no negative consequences for endangered forests.

These commitments, among others, mean that 100% of the paper used in our books has the PEFC label.

Important information: The activities proposed in this book should be completed in a separate notebook or on sheets of paper, not in the book itself.

The links to webpages which appear in this book have been checked before printing. The publisher cannot be liable for any changes or modifications which occur after the date of publication.

© GRUPO ANAYA, S.A., 2021 - Juan Ignacio Luca de Tena, 15 - 28027 Madrid - Printed in Spain.

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior permission of the publishers.

Index Scientific knowledge..................................................7 Summary • 1 Scientific research • 2 Physical quantities and units • 3 Measuring physical quantities. Errors • 4 Analysing experimental data • The final challenge

1. THE ATOM AND THE PERIODIC TABLE..................15

6. KINEMATICS............................................................................55 Summary • 1 Frame of reference • 2 Quantities of motion • 3 Types of motion • 4 Linear motion • 5 Circular motion • 6 Interpreting graphs • The final challenge

7. NEWTON’S LAWS OF MOTION....................................63

Summary • 1 The first atomic models • 2 Atomic spectra and Bohr’s model • 3 Quantum model of the atom • 4 The periodic table of the chemical elements • The final challenge

Summary • 1 Forces • 2 Everyday forces • 3 Newton’s laws of motion • 4 Newton’s laws in everyday motion • The final challenge

2. CHEMICAL BONDS AND INTERMOLECULAR FORCES........................................................................................ 23

Summary • 1 Historical evolution of the study of the universe • 2 Gravitational forces • 3 Applications of the universal law of gravity • 4 Artificial satellites in orbit • The final challenge

Summary • 1 Chemical bonds • 2 Ionic bonds • 3 Covalent bonds • 4 Intermolecular forces • 5 Metallic bonds • 6 Summary of the properties of chemical compounds • The final challenge

3. CARBON COMPOUNDS.......................................................31 Summary • 1 The carbon atom • 2 Allotropic forms of carbon • 3 Molecular formulas and models • 4 Hydrocarbons • 5 Oxygenated and nitrogenated carbon compounds • 6 Molecules of particular interest • The final challenge

4. CHEMICAL REACTIONS: FUNDAMENTALS.........39 Summary • 1 Chemical changes • 2 Reaction rate • 3 Amount of substance • 4 Stoichiometric calculations • 5 Energy in chemical reactions • The final challenge

5. SOME IMPORTANT CHEMICAL REACTIONS......47 Summary • 1 Acids and bases • 2 Combustion reactions • 3 Importance of combustion reactions • 4 Synthesis reactions • The final challenge

8. FORCES IN THE UNIVERSE............................................71

9. FORCES IN FLUIDS. PRESSURE.................................79 Summary • 1 Pressure • 2 Hydrostatic law • 3 Archimedes’ principle • 4 Pascal’s law • 5 Atmospheric pressure • 6 Meteorological concepts • The final challenge

10. MECHANICAL ENERGY AND WORK........................ 87 Summary • 1 Energy • 2 Work • 3 Power • 4 Kinetic energy • 5 Potential energy • 6 Conservation of mechanical energy • 7 Energy transport via mechanical waves • The final challenge

11. THERMAL ENERGY AND HEAT ...................................95 Summary • 1 Thermal energy. Temperature • 2 Thermal equilibrium. Heat and heat transfer • 3 Effects of heat • 4 Heat engines • 5 Energy loss • The final challenge

DUAL FOCUS

k oo b r u o y f o t In this par ind... you will f

du al FOCUS

4 DUAL FOCUS

9

Available at

www.anayaeduc

that accompanies

RESOURCE

Y PHYSICS AND CHEMISTR

acion.es

this book.

SECO EDU

BANK

PHYSIC CHEMI

4

SECONDARY EDUCATION

SECONDARY EDUCATION

un

78846

I S B N 978-8

Go to the

PHYSICS AND CHEMISTRY

SUMA

it

piezaS

cion.es

du al FO

www.anayaeduca

2

Scan this code to consult the glossary for this unit.

Chemical bonds and intermolecular forces O

Chemical bonds O

lower

the energy of the system

Ionic

Covalent

Metallic

by acquiring

results in

results in

results in

noble gas electron configuration

crystalline lattice

depending on

described by

bound by

empirical formula

intermolecular forces

+

Lewis Diagram

Na ++ O Cl Cl

Vocabulary The page that shows the key vocabulary you will encounter in the unit.

O

Na+

Cl

+ O

+

This section contains activities for practising and applying the key vocabulary in the unit.

types

Octet rule Na

Focus on English

Cl –

Na Cl Cl

O O

covalent crystalline lattices

molecules

The Final Challenge!

crystalline lattice

Each unit ends with a task or challenge to help you develop your skills by applying your knowledge in a different context.

NaCl Na+ O2– Cl2

Na+

Na2O

O2

Focus on English 1

Listening and Speaking. Listen and repeat the most important terms of this unit, paying attention to their pronunciation.

2 Reading and Writing. Read the outline

NK BANK NGUAGE BA NK LABANK LANGUAGENK NGUAGE BA NK LA BANK LANGUAGENK LANGUAGE BA BA GE UA LANG UAGE BA NGUAGE BANK BANK LAUAGE BANK LABANGNK LANGUAGE LANGUAGE LANG LANGUAGE

The final challenge

on chemical bonds between atoms and write a sentence in your notebook that summarizes the content of each branch.

23

Types of substances We are surrounded by objects made from the types of substances that we have studied. We can use this fact to create a game that will help us to learn the properties of the different types of substances in a fun way

Work in groups. Split the class into four groups. Assign one of the following substances randomly to each group: ionic, covalent, reticular, molecular, metallic.

We can find examples of the sustances studied in the unit in everyday objects.

Working as a team, each group must choose everyday objects made from the type of substance assigned. One object is assigned to each member, who has to take a photograph of the assigned object.

We can find examples of the substances we have studied among everyday objects.

Create a game Cardboard sheets of the same colour are distributed among all the groups. Each group must cut out a piece of 8 × 12 cm and prepare cards with the structure shown in the example. With the teacher’s assistance, the students must complete the cards, one for each of the selected objects.

In addition, small photographs of 5 × 5 cm with each of the objects are made.

PROPERTIES Aggregation state: solid Melting/boiling temperature: low Hardness: soft Fragile: No Soluble in water: No Conducts electricity: No

TYPE OF SUBSTANCE Molecular

OBJECT Comb Let’s play: Guess who I am Place the photographs facing up in a random order. Place the cards facing down and shuffle them. Toss a coin to decide which team will ask questions first.

The team asking the questions chooses a card, and the other team hands it over without looking at the card. The first team must try to guess the object in the card.

The team can ask up to three questions on the properties of the object. With this information, the aim is to figure out the type of substance that is indicated in the card. If they guess right, they can ask up to three more questions, this time about the appearance of the object. The questions must only admit YES or NO as an answer. As the team asking the questions rules out objects, they must turn over the photographs of the discarded objects until they can guess the correct one.

The team that guesses the most objects in less time wins.

Basic exercises The activities on these pages work on the basic unit content, as well as the different language skills.

Expand your knowledge

There are substances with surprising properties. Find videos on the Internet on the properties of sulphur hexafluoride or nitinol.

Did you know about these substances? What type of substances do you think they are?

Keep on researching to find out why they have the surprising properties shown in the videos.

30

3

MOLE CULA R FORM ULAS

4

AND MODE LS ls

Molecular models

formulas and mode

ular 3.1 Types of molec

of substances. ing the composition element t ways of express of atoms of each There are differen indicates the number t isomers The molecular formula allow telling differen le, but it does not ed and semiextended present in the molecu extend ral, structu using the apart. This requires formulas.

Semiextended formula Extended formula Molecular formula H

C4H10

H

H

H

H

C

C

C

C

H

H

H

H

CH3

H

CH2

CH2

CH3 CH3

Stick model

CH3 CH3

CH3

in the molecules ment of the atoms the spatial arrange used ones are In addition, to know . The most widely molecular models it is necessary to use illing models. stick, and space-f the stick, ball and

CH2 CH2 Ball-and-s tick

model

SDG Watch the video on Goal 12 and complete the associated activities at anayaeducacion.es.

Unit 3

HYDR OCAR BONS

C. They are only by H and compounds formed low fusion and Hydrocarbons are water and having being insoluble in characterised by boiling temperatures. t types: differen into divided are named They are by single bonds and carbons are joined react well with • In alkanes all the good fuels, as they They stand out as with the suffix –ane. oxygen. structure and are named their in bond and are least one double help fruit to ripen • Alkenes have at They are combustible, with the suffix –ene. ing. containers and packag –yne. The also used to make and have the suffix least one triple bond • Alkynes have at e. ethyne, or acetylen They are nature. best-known one is in present widely hydrocarbons are The most alkane or alkene.

• In addition, cyclic cyclo- before the e. named with the prefix cyclohexane and benzen important ones are

Commitment to SDGs

.

Understand, think, apply.. tion Search for informa ental about the main environm fossil fuels. consequences of burning e the uses of 7 Writing. Describ and ethyne. ethane, ethylene, Listening. Listen to thee at 8 m availabl audio on petroleu and make a list anayaeducacion.es s obtained of the various product from it.

The resource bank contains audiovisual material that focuses on Sustainable Development Goals.

6

hydrocarbons Some frequently used

CH2 CH2

re n and nomenclatu

3.2 Formulatio

concepts of be familiar with the compound one must l properties, even To name a carbon with similar chemica containing (a group of atoms functional group longest carbon chain nds), main chain (the differ in the length in different compou series (which only and homologous a functional group) of the chain).

Priority

Functional group

1

–COOH

2

–COO–

Organic family

Carboxylic acid Ester

3

–

–NH2; –NH–; –N–

6

C=C

7

-ol

-ino -ano

.

Understand, think, apply..

in the following

te and the comple

a) CH3

c) CH3

34

6

C

C

of

CH2

CH3

CH3

b)

CH3 C

CH

d)

H2C

Skills

also used for domestic Butane and propane are s they are delivered in heating and cooking. Sometimein liquid form. canisters or tanks

-eno

Alkene

ar formula 4 Find the molecul the following compounds: structural formula

of methane and ethane Natural gas is made mostlythat pollutes the least. It fuels and is one of the fossil and cooking. is piped to homes for heating

CH

-amina

Amine

Alkane

C–C

9

CH ing model Space-fill

-ona

Alkyne

C~C

8

CH

-al

Alcohol

–OH

5

CH

-ato de -ilo

Ketone

–CO–

4

Suffix

Ácido –oico

Aldehyde

–CHO

CH CH2 CH2

CH3

al group 5 Identify the function to which family they belong: compounds and indicate c) CH3—CH2—NH2 a) CH3—CH—CH2 b) CH3OH

d) CH4

a mix of hydrocarbons with Gasoline and diesel are atoms and are used mainly between 5 and 20 carbon vehicles. as fuel for

of the acetylene burns is one such The temperature at which it useful for welding metals, highest possible, making steel. as copper, aluminium or 35

The suggested activities have been specially designed to gradually and continuously develop the four language skills. The main skill worked on in each activity is highlighted:

Speaking Listening

Reading Writing

DUAL FOCUS

+

4

CE BANK RESOURpanie s this book.

Go to the

Available

ion.es

ducac at www.anayae

788469

9

880319

In this section of the book, the key information is presented in graphic form, using diagrams and illustrations to help you learn each concept.

SUMA

piezaS

8450905

9

unit

Key concepts

SECONDARY EDUCATION 98-8031I S B N 978-84-6

3

…

t r a p is h t in d An

PHYSICS AND CHEMISTRY

that accom

+

du al FOCUS

CAR BON COM POU NDS

Allotropic forms formed from the same Allotropes are substances arranged to form element but with their atoms therefore with different different structures, and properties.

The carbon atom

branch or organic chemistry, is the The chemistry of carbon, the molecules formed by carbon of chemistry that studies also contain other elements such as may and hydrogen, which etc. oxygen, sulphur, nitrogen,

y of allotropes, Carbon has a great varietnd (natural), or such as graphite or diamo n nanotubes carbo or ne, fullere ene, graph (artificial).

form ent compounds, and can .

Carbon can form many differ with a great variety of atoms up to four covalent bonds

Fructose C6H12O6

Lactose C12H22O11

Cellulose C6H10O5

In a breakfast you can find many different molecules formed by carbon, hydro and other elements. Orgagen chemistry is very prese nic nt in our daily lives.

Caffeine C8H10N4O2

can have the same Two or more compounds gements. These are formula in different arran known as isomers.

t

ular formula types of isomers, the molec Because there are so manyto differentiate. This is why the expanded is sometimes not enough las are used. and semi-expanded formu representing ent molecular models for There are several differsions. This is done using physical models molecules in three dimen studied the stick, ball and stick, and and simulations. We have space-filling models.

1 Electron configuration The number of electrons in the last energy level of an atom determines its chemical properties. The electron configuration is how the electrons are arranged in the shell of the atom.

14

Electrons

has orbited and The Juno space probe, which n nanotubes in its carbo studied Jupiter, contains structure.

models Molecular formulas and

rich. Carbon can Organic chemistry is very triple bonds. form single, double and can form when the chains carbon atoms linear or cyclic, they join together can be and can have branches.

uni

and hydrogen, organic In addition to oxygen atoms. compounds can include other

so great that carbon The pressure in Jupiter is fall in the form of a can can form diamonds that ‘diamond rain’.

, is ith CO 2 the ther w to d ne, toge ributor Metha ortant cont It is producenic p . an im ouse effect ion of orga rm fo it greenhe decompos ned in the gy. by th which is bur roduce ener p mattertural gas to of na

The electron configuration of an atom follows certain rules. One of the best tools is Möller’s diagram, which indicates the order of filling of the levels. The valence electrons (those in the last orbital occupied) determine the chemical properties of the atom.

Periodic properties The periodic system allows distinguishing metals, non-metals, semi-metals, and noble gases. The order in which the elements are placed in the periodic table corresponds to the increase in the electron affinity (EA) and ionisation energy (IE) of the elements.

15

Discovery of the neutron In 1932, Chadwick confirmed the existence of a new particle, the neutron, with a similar mass to that of the proton and neutral charge. This allowed linking the mass of an atom to the number of particles contained in it.

Chadwick

Periodic system Chemical elements are ordered according to their chemical and physical properties in the periodic table of the elements. In addition, the table specifies their mass number and atomic number, which indicate the number of protons and neutrons in the nucleus of the atom.

In the periodic system there are 7 periods, or rows, and 18 groups, or families of elements. The atoms of elements in the same period have the same number of shells or main energy levels, and the atoms of elements in the same group have the same electron configuration for their valence electrons.

Activities The resource bank contains activities for you to practise what you have learnt.

8

Atomic mass The theoretical mass of an atom is the sum its protons and neutrons (we do not consider of the masses of electrons as this is negligible compared to the mass of the that of the protons and neutrons).

Not all the atoms of a given chemical element have the same mass. The elements have several isotopes.

anayaeducacion.es You can use the activities from the resource bank to review the content of these fact files.

9

7

The

Resource bank www.anayaeducacion.es

This is where you will find resources, techniques and activities to help you consolidate your knowledge.

The final challenge

Types of substances

un

Go to www.anayaeducacion.es, and follow the steps at the beginning of your Spanish book.

Work in groups. Split the class into four groups.

Assign one of the following substances randomly to each group: ionic, covalent, reticular, molecula metallic. r, Working as a team, each group must choose everyday objects made from the type of substance assigned . One object is assigned to each member, who has to take a photograph of the assigned object.

We can find examples of the substances we have studied among everyday objects.

Create a game Cardboard sheets of the same colour are distribute d among all the groups. Each group must cut out a piece of 8 × 12 cm and prepare cards with the structure shown in the example. With the teacher’s assistance, the students must complete the cards, one for each of the selected objects.

In addition, small photogra phs of 5 × 5 cm with each of the objects are made.

Your book contains references to the online resources you can use to learn more about each topic and to develop your English language skills.

it

We are surrounded by objects made from the types of substances that we have studied.

We can use this fact to create a game that will help us to learn the properties of the different types of substances in a fun way

3

Carbon compounds

Scan this code to consult the glossary for this unit.

The carbon atom We can find examples of the sustances studied in the unit in everyday objects.

has

presents

forms

PROPERTIES

Aggregation state: solid Melting/boiling tempe rature: low Hardness: soft Fragile: No Soluble in water: No Conducts electricity: No

Characteristics

Types of bonds

TYPE OF SUBSTANC E

Molecular

Types of chains

Single

OBJECT

Double

Comb Let’s play: Guess who I am

Allotropic forms

Hydrocarbons

H H

H

C

C

H

H

C

C

H

C

H

H

H

C

C

Diamond

Alkanes

Alcohols

Cyclic

Graphite

Alkenes

Amines

Fullerene

Alkynes

Aldehydes

Graphene

Cyclic

Ketones

H

C

C

C C

H

C

Oxygenated and nitrogenated compounds

Linear

Triple

Place the photographs facing up in a random order.

Place the cards facing down and shuffle them. Toss a coin to decide which team will ask questions first.

The team asking the question s chooses a card, and the other team hands it over without looking at the card.

The first team must try to guess the object in the card.

The team can ask up to three questions on the propertie s of the object. With this information, the aim is to figure out the type of substanc e that is indicated in the card. If they guess right, they can ask up to three more questions, this time the appearance of the about object. The questions must only admit YES or NO answer. As the team asking as an the questions rules out objects, they must turn the photographs of the over discarded objects until they can guess the correct The team that guesses one. the most objects in less time wins.

Organic compounds

C

H

C

C C

Molecules of particular interest Fats Carbohydrates Proteins Polymers

Carboxylic acids

C

Esters

Focus on English Expand your knowledge

There are substances with surprising properties. Find properties of sulphur hexafluor videos on the Internet on the ide or nitinol.

Did you know about these substances? What type of substances do you think they are?

Keep on researching to find out why they have the surprising propertie videos. s shown in the

30

1

SDG Watch the video on Goal 12 and complete the associated activities at anayaeducacion.es.

NK LANGUAGE BA BANK UAGE BANK GE BANK LANGUAGE NK NK LANG UA LANGUAGE BA NGUAGE BANK LANG BANK LANGUAGE BA LA GE UA NG NK NK LA GE BA LANGUAGE BA LANGUAGE BANK NK LANGUA LANGUAGE BA

Resources organised

by unit

Interactive activities

8

All the resources are clearly organised so you can find the ones related to your unit.

l Audiovoisuuarces

res

Glossary

QcoRde

Listening

and Speaking. Listen and repeat the most important terms of this unit, paying attention to their pronunciation.

2 Reading and Writing.

Read the outline on the compounds of carbon and write a sentence in your notebook that summarizes the content of each branch.

31

un

3

it

Scan this code to consult the glossary for this unit.

Carbon compounds The carbon atom

has

Characteristics

Types of bonds

H

H

C

C

H

H

C

C

forms

Allotropic forms

Organic compounds

Types of chains

Oxygenated and nitrogenated compounds

Hydrocarbons

Molecules of particular interest

Single

Linear

Diamond

Alkanes

Alcohols

Fats

Double

Cyclic

Graphite

Alkenes

Amines

Carbohydrates

Fullerene

Alkynes

Aldehydes

Proteins

Graphene

Cyclic

Ketones

Polymers

Triple H

presents

H

H

C

C C

H

H

C

C

H

H

C

C C

C

H

Carboxylic acids

C

C

C C

Esters

Focus on English Listening and Speaking. Listen and repeat the most important terms of this unit, paying attention to their pronunciation.

1

2 Reading and Writing. Read the outline

ANK B E G A U ANK G B N E A L G A U G N LA ANK B E G K A N U A G B N E BANK A G L E A G U A G U N G A K N L N A L BA LANGUAGE LANGUAGE BANK NGUAGE BANK E BANK

on the compounds of carbon and write a sentence in your notebook that summarizes the content of each branch.

31

1

THE CARBON ATOM

1.1 Singularity of the carbon atom

Understand, think, apply...

Carbon is the fourth most abundant element in the universe, and can form an enormous number of substances due to its great capacity to bind to other carbon atoms and form long chains, in which hydrogen is always present.

1 Writing. CO and CO2 are

considered inorganic molecules.

Explain why, using the definition of the chemistry of carbon.

2 Speaking. Carbon and silicon have

The chemistry of carbon is the part of chemistry that studies the molecules that contain carbon and hydrogen, which can also contain other elements. These molecules are known as carbon compounds, or organic compounds.

similar properties. Is silicon-based life possible?

3 The following compounds, forms of C4H8, are isomers. Explain why.

H

1.2 Characteristics of carbon Carbon has four valence electrons and can form up to four covalent bonds with other atoms. It can bond to other atoms by single, double or triple bonds; its chains can be linear, cyclic, and branched, andHgenerally H include C, H, O, N. C ofCeach C It is common to find molecules with the same number of atoms

H

element but joined in different ways. These molecules that share the same H H H molecular formula.

H

C

H

H

H

C

C

H

H

Double bonds H H

H

H

H

C

C

C

H

H

H

H

H H

H

C

C

H

C H

H

C

C

H

H

H

HH

C

C

H H

H

H

H

C

C

H C

H

C

H

C

Types of bonds between carbon atoms H Single bonds

H

HH

C C H H H HH bondsH C C H Triple

H

H

Types of carbon chains and atoms with which carbon may bond Cyclic or closed chain

Linear or open chain

C

C

C

C

C C

C

C

H

32

C

O H

C

C

C

C

H

C H

C

C

C

Oxygen

H C

C

C

Hydrogen

H

Chains with branches

C

Nitrogen

H H

H H

N C H

C

H

H

H H

C

H

H

H

C

C

H

C

C

H

H

H

C

H

C

H

HH CC CC HH

H

H

C

2

ALLOTROPIC FORMS OF CARBON

Unit 3

2.1 Diamond and graphite Allotropes are substances formed from a single element in which the atoms form different structures and have different properties. The two allotropes of carbon are diamond and graphite.

Diamond consists of a tetrahedral crystalline lattice of covalent bonds.

Great energy is required to break them, so it is extremely hard, non-soluble and does not conduct electricity. Instead, graphite forms a flat lattice in which the fourth electron can move freely between layers, has a high temperature of fusion, is soft and breaks into layers, and conducts electricity.

Carbon allotropes Diamond

Graphite

Other allotropic forms of carbon have physical and chemical properties that hold great promise for the future.

New carbon allotropes Fullerene

Fullerene is the first synthetic allotrope. Its most common structure has 60 carbons, C60. Researchers believe it could be very useful for delivering medicine to cells.

NASA has published the detection of fullerene in various nebulae.

Graphene

Graphene is a sheet of graphite one atom thick that has surprising properties: it is an excellent conductor, very durable, flexible and transparent.

It is a relatively new compound and considered a 21st century material.

33

3

MOLECULAR FORMULAS AND MODELS

3.1 Types of molecular formulas and models There are different ways of expressing the composition of substances.

The molecular formula indicates the number of atoms of each element present in the molecule, but it does not allow telling different isomers apart. This requires using the structural, extended and semiextended formulas.

Molecular formula

Extended formula

C4H10

H

H

H

H

H

C

C

C

C

H

H

H

H

Molecular models CH3 CH3

Stick model

CH3 CH3

Semiextended formula CH3

H

CH2

CH2

CH3

In addition, to know the spatial arrangement of the atoms in the molecules it is necessary to use molecular models. The most widely used ones are the stick, ball and stick, and space-filling models.

3.2 Formulation and nomenclature

CH2 CH2

Ball-and-stick model

CH2 CH2

To name a carbon compound one must be familiar with the concepts of functional group (a group of atoms with similar chemical properties, even in different compounds), main chain (the longest carbon chain containing a functional group) and homologous series (which only differ in the length of the chain).

Functional group

Organic family

Suffix

1

–COOH

Carboxylic acid

Ácido –oico

2

–COO–

Ester

-ato de -ilo

3

–CHO

Aldehyde

-al

4

–CO–

Ketone

-ona

5

–OH

Alcohol

-ol

6

–NH2; –NH–; –N–

Amine

-amina

7

C=C

Alkene

-eno

8

C~C

Alkyne

-ino

9

C–C

Alkane

-ano

–

Priority

CH

CH

CH Space-filling model

CH

Understand, think, apply...

4 Find the molecular formula and the complete structural formula of the following compounds: a) CH3

C

C

CH2

CH3

CH3 b) CH3

c) CH3

34

C

CH d) H2C

CH CH2 CH2

CH3

5 Identify the functional group in the following compounds and indicate to which family they belong: a) CH3—CH—CH2

c) CH3—CH2—NH2

b) CH3OH

d) CH4

4

HYDROCARBONS

Unit 3

Hydrocarbons are compounds formed only by H and C. They are characterised by being insoluble in water and having low fusion and boiling temperatures.

They are divided into different types: • In alkanes all the carbons are joined by single bonds and are named

Understand, think, apply...

6

with the suffix –ane. They stand out as good fuels, as they react well with oxygen.

• Alkenes have at least one double bond in their structure and are named

with the suffix –ene. They are combustible, help fruit to ripen and are also used to make containers and packaging.

• Alkynes have at least one triple bond and have the suffix –yne. The

best-known one is ethyne, or acetylene.

• In addition, cyclic hydrocarbons are widely present in nature. They are

named with the prefix cyclo- before the alkane or alkene. The most important ones are cyclohexane and benzene.

Search for information about the main environmental consequences of burning fossil fuels.

7 Writing. Describe the uses of ethane, ethylene, and ethyne.

8

Listening. Listen to the audio on petroleum available at anayaeducacion.es and make a list of the various products obtained from it.

Some frequently used hydrocarbons

Natural gas is made mostly of methane and ethane and is one of the fossil fuels that pollutes the least. It is piped to homes for heating and cooking.

Gasoline and diesel are a mix of hydrocarbons with between 5 and 20 carbon atoms and are used mainly as fuel for vehicles.

Butane and propane are also used for domestic heating and cooking. Sometimes they are delivered in canisters or tanks in liquid form.

The temperature at which acetylene burns is one of the highest possible, making it useful for welding metals, such as copper, aluminium or steel.

35

5

OXYGENATED AND NITROGENATED CARBON COMPOUNDS

Among the carbon compounds that include other elements in addition to C and H, the following are worth noting: H

• Alcohols, which have a hydroxyl group, –OH, joined to a carbon by a

single bond. One example is ethanol, used to disinfect wounds, and present in alcoholic drinks.

Aldehyde

Ketone

O

O

C

C

H

H

CH3

CH2

C

H

H

H

O

C

C

C

C

NH2

H

H

CH3

C H

CH2

Propyamine

H C

OH

Ethanol

the suffix –yl.

group, –CO–, which can occupy different positions in the carbon chain; at the ends, in the case of aldehydes, or in the middle, in ketones.

H

CH3 - CH2OH

• Amines, which are derivatives of ammonia, NH3, and are named with • Aldehydes and ketones are characterised by containing the carbonyl

H

CH2

CHO

Propanal

C

H

The most widely used ones are formaldehyde, a gas with a very strong odour, acetone as a solvent, and sugars in living organisms.

C

C

CH3

with –oic followed by acid. The most important one is ethanoic or acetic acid (vinegar). an alkyl group. First the chain joined to the O atom is named with the suffix -yl, and then the chain joined to the C atom of the carboxyl group is named with the suffix –ate.

O OH

H

• Carboxylic acids contain the group –COOH, and are named as ending

• Finally, esters, in which the H in the carboxyl group is substituted with

H

COOH

Ethanoic acid CH3

COO

CH3

Methyl ethanoate

Understand, think, apply...

9

Reading. Search for information on the importance of 1,2,3-Propanetriol or glycerol.

12

10 Write the formula or name of the following alcohols: a) CH3—CH2—CH2—CH2OH b) CH3—CH2—CHOH—CH3

13 Write the formula or name, as appropriate, of the following compounds:

c) Pentan-3-ol.

a) Pentanoic acid b) 3-methylpentanoic acid

11 Find the condensed structural formula and the

names of the compounds shown in these molecular models: a)

36

What is known as sugar is a disaccharide called sucrose formed by glucose and fructose, two simple sugars. Find the linear formula of glucose and fructose and identify their functional groups.

b)

c) CH3—CH2—CH2—COOH d) CH3—CH(CH3)—CH(CH3)—COOH

14

Reading. Methanoic acid is present in the defensive liquids some ants emit. Write the formula of this acid, find its other name, and the reason behind it.

6

MOLECULES OF PARTICULAR INTEREST

Unit 3

The most important nutrients we ingest are all carbon compounds: • Fats result from joining a long-chain carboxylic acid with glycerol. They

have a structural and energy role.

• Carbohydrates are formed by C, H and O, and as the most important

functional group an aldehyde or ketone.

• Proteins are macromolecules formed by C, H, O and N with a three-

dimensional structure. The compounds that form proteins are known as amino acids, and have two functional groups: a carboxylic acid and an amine group. They form part of all animal and vegetable cells.

On the other hand, polymers are macromolecules formed from simple monomers, among which cellulose (natural) or polyethylene (synthetic) stand out and which are usually not biodegradable.

Examples of molecules of particular interest

Fat-rich foods include oils, butters, lards, and any food that contains a lot of these such as sausages and industrial pastries. They should be consumed in moderation.

Bread, cereal, rice and pasta are all rich in carbohydrates.

Fruits are high in fructose and glucose. These foods should form the basis of our diet, but excessive consumption of sugar should be restricted.

Meat, fish, eggs and legumes are in protein. It is important to consume enough proteins, but not in excessive amounts.

Polymers are part of our everyday lives. Plastic utensils, toys, clothing, packaging and containers are all made of one type of polymer or another, depending on their use.

Check the resource bank at anayaeducacion.es to find out the resources associated to this unit.

37

Molecular models The final challenge

We have studied the various types of molecular models, which provide information on the shape of organic molecules. In this section we will learn how to build our own physical models with coloured plasticine, using the digital models from the Avogadro software.

Work in groups. Split the class into four groups and assign a different functional group to each one.

Working in collaboration, each group must choose a compound containing the functional group, write down its molecular formula, and using the Avogadro software draw its stick and ball molecular model.

Start with simple compounds like propane, ethene, propyne, cyclobutane, ethanol, trimethylamine, methanal, acetone, ethanoic acid, methyl ethanoate or benzene.

Then, each member of the group must reproduce the molecular model drawn using coloured plasticine.

Build your own model with plasticine Use the plasticine to mould several balls that will be used to build models of atoms of an element according to the specified colours.

All the balls should have approximately the same size, although balls corresponding to hydrogen, white, can be somewhat smaller than the others.

The sticks represent the bonds. Cut them carefully into fragments about 4 cm long. When necessary, use double or triple bonds by placing two or three sticks between two plasticine balls.

Count the number of atoms and bonds needed. Build them with plasticine and sticks, respectively, and lastly assemble the various elements in the arrangement shown in the digital model. Rotate the model in the computer to get a good view of its three-dimensional shape.

Show your model and add information Finally, show your molecular model to the rest of the class. They should formulate and name the compound corresponding to your model. Did they manage to name it?

You can also build models of the allotropic forms of carbon. Look at the models of the structures of diamond and graphite shown in this unit and try to build a model of these reticular covalent substances.

38

Simple bond

Double bond

Hydrogen

Triple bond

Carbon Oxygen Nitrogen

A final challenge Can you make a model of fullerene, which has 60 carbon atoms? As you can see, its structure combines pentagons and hexagons. Start by building a pentagon. Each side of the pentagon should also be the side of a hexagon. Keep assembling pentagons and hexagons until the structure is complete. To make it easier, find out how many pentagons and hexagons are in fullerene.

SDG Watch the video on Goal 4 and complete the

associated activities at anayaeducacion.es.

www.ana SECONDARY EDU

SE ED

CATION

PHYSICS AND C H E M I S T RY

PHYSICS AND CHE MISTRY

PH CH

Go to the

RESOURCE

BANK that accom panies thi s book.

Available

DUAL FOCUS

at www.anay aed

ucacion.e

s

4 SECONDARY EDUCATION 031- 9

880319

8450905

4

I S B N 97884-6 98-8

788469

SUMA

piezaS

SECONDARY EDUCATION

! d n u o r k oo 9

cion.es www.anayaeduca

d u a l FOCUS

+

b e h t n r u T Nee

SECONDARY EDUCATION

4

? s u c o f e d mor piezaS

SUMA

PHYSICS AND CHEMISTRY

PHYSICS AND CHEMISTRY

dual

PHYS CHE

Go to the

NK RESOURCE BA this book. that accompanies

n.es .anayaeducacio Available at www

DUAL FOCUS

d u a l FOCUS

4

unit

3

CARBON COMPOUNDS

The carbon atom The chemistry of carbon, or organic chemistry, is the branch of chemistry that studies the molecules formed by carbon and hydrogen, which may also contain other elements such as oxygen, sulphur, nitrogen, etc.

Carbon can form many different compounds, and up to four covalent bonds with a great variety of atoms.

Fructose C6H12O6

Lactose C12H22O11

In a breakf a many differ st you can find formed by c ent molecules and other e arbon, hydrogen chemistry islements. Organic very p our daily liv resent in es.

Cellulose C6H10O5

Caffeine C8H10N4O2

In addition to oxygen and hydrogen, organic compounds can include other atoms.

Two or more compounds can have the same formula in different arrangements. These are known as isomers.

14

Organic chemistry is very rich. Carbon can form single, double and triple bonds.

The chains carbon atoms can form when they join together can be linear or cyclic, and can have branches.

Allotropic forms Allotropes are substances formed from the same element but with their atoms arranged to form different structures, and therefore with different properties.

The pressure in Jupiter is so great that carbon can form diamonds that can fall in the form of a ‘diamond rain’.

Carbon has a great variety of allotropes, such as graphite or diamond (natural), or graphene, fullerene, or carbon nanotubes (artificial).

The Juno space probe, which has orbited and studied Jupiter, contains carbon nanotubes in its structure.

Molecular formulas and models Because there are so many types of isomers, the molecular formula is sometimes not enough to differentiate. This is why the expanded and semi-expanded formulas are used.

There are several different molecular models for representing molecules in three dimensions. This is done using physical models and simulations. We have studied the stick, ball and stick, and space-filling models.

CO 2, is h it w r e h r to the e, toget Methan rtant contributoproduced an impo se effect. It is f organic u greenho decomposition oin the form by the ich is burned e energy. h uc matter wral gas to prod of natu 15

3 Hydrocarbons Hydrocarbons are carbon compounds formed exclusively by hydrogen and carbon. They are classified into alkanes, alkenes and alkynes.

Their nomenclature follows certain rules that allow identifying them.

Alkane

Alkene Alkyne

fuel the most important ones are their use as Hydrocarbons have many uses. Some of s or other materials such as PVC. and their use to create plastic

Cyclic hydrocarbons Cyclic alkanes and alkenes are very common in nature.

They are part of many compounds, and some, such as benzene (C6H6), are used in the manufacture of many substances.

Benzene (C6H6) and its derivatives are known as aromatic compounds. Benzene is one of the 20 most produced chemical products and has a wide range of uses.

16

Alcohols An alcohol is a carbon compound characterised by having a hydroxyl group, -OH, joined to a carbon by a simple bond.

The preparation of alcoholic drinks follows different processes, but they are all based on the process of converting glucose into ethanol with the action of yeasts.

Amines Amines are derivatives of ammonia, NH3, where one, two or all three hydrogens have been substituted by groups derived from alkanes, alkyl groups.

Aldehydes and ketones Aldehydes are compounds with a carbonyl group joined to hydrogen. In ketones the carbonyl group is joined to two carbons.

Yeasts Sugar

Ethanol

Carboxylic acids These have a terminal carbon joined to an oxygen by a double bond and to a hydroxyl by a single bond. This group is known as a carboxyl group, -COOH.

Esters They have a terminal carbon joined to an oxygen by a double bond and to a hydroxyl by a single bond. This group is known as a carboxyl group, -COOH.

Molecules of particular interest Nutrients are molecules that we need to ingest enough amounts of for the correct functioning of our organism. The most important groups are fats (saturated and unsaturated), carbohydrates and proteins.

A polymer is a macromolecule formed by the union of several simple identical molecular structures, the monomers.

anayaeducacion.es You can use the activities from the resource bank to review the content of these fact files.

17