Polymers

Crisp packets are often made from poly(propene) coated with a thin layer of aluminium on the inside.

Poly(propene) is a polymer made from the monomer propene, CH₂CHCH₃.

What is the relative formula mass of propene?

(relative atomic masses: C = 12, H = 1)

Describe how monomer molecules combine to make polymers.

Crisps go stale when exposed to the atmosphere.

In an experiment some crisp packets were made from aluminium, some from poly(propene) and some from poly(propene) coated with aluminium. These packets were tested.

Figure 5 shows the results.

Low porosity is an advantage of using poly(propene) coated with aluminium as it prevents the crisps from becoming damp.

Explain, using Figure 5, one other advantage of using poly(propene) coated with aluminium.

The aluminium coating can be replaced by a very thin layer of material called a nanosheet.

The nanosheet is made from amino acids and is less than 100 nm thick.

Explain why the nanosheet layer would be better than aluminium as a coating for crisp packets.

Nanosheet layers can be made from amino acids.

An equation showing a reaction of an amino acid, C₂H₅NO₂, is

Calculate the mass of water formed when 105 g of this amino acid reacts.

(relative formula masses: C₂H₅NO₂ = 75, H₂O = 18)

Some crisps contain malic acid.

The structure of one molecule of malic acid is shown in Figure 6.

Malic acid has two types of functional group.

One type is the –COOH functional group.

Give the name of this functional group.

Name the other functional group.

Ethanol can be produced by the fermentation of carbohydrates.

What conditions are necessary for fermentation?

A carbohydrate has the formula C₁₂H₂₄O₁₂.

Complete the equation for the fermentation of this carbohydrate to make ethanol and carbon dioxide only.

C₁₂H₂₄O_{12 ........}

Ethanol can be oxidised to make ethanoic acid. One use of ethanoic acid is to make a monomer.

This monomer is polymerised to make the addition polymer PVA, used as a glue.

The structure of the monomer is shown in Figure 14.

Draw a diagram to show the structure of the repeating unit of PVA.

*(c) Babies may wear bamboo nappies or disposable nappies. Both types of nappy absorb liquid.

The bamboo in bamboo nappies comes from a fast growing plant. A bamboo nappy can be washed and used again many times. When a bamboo nappy is placed in landfill, it will rot away quickly.

Disposable nappies contain a polymer made using crude oil. 1 g of a typical polymer used in disposable nappies can absorb about 150 g water. When a disposable nappy is placed in landfill, it may take over 400 years to decompose.

Discuss, using the information given, the advantages and disadvantages of bamboo nappies and disposable nappies. Include in your answer a brief description of how a nappy could be tested to see how much water it will absorb.

Figure 1 shows a metal spoon.

This spoon is made of silver.

Give a reason why silver is a suitable material to use for making a spoon.

Some spoons are made of wood or plastic, not metal.

The raw material for wooden spoons is trees and the raw material for plastic spoons is crude oil.

Explain an advantage, other than cost, of using wood rather than plastic.

Some people wear spectacles so that they can see more clearly.

Which property of glass makes it suitable for use in spectacles?

Some spectacles have a coating made of nanoparticles on the glass.

Which statement describes nanoparticles?

One nanoparticle has a cube shape that is shown in Figure 2.

Calculate the surface area of this nanoparticle.

surface area = area of one face × number of faces

The structure of one molecule of compound L is shown in Figure 12.

State what the lines between the atom symbols represent in Figure 12.

Explain why compound L is an alkene.

1 molecule of compound L has a mass of 9.302 × 10^–23g.

82,500 molecules of compound L combine to form 1 polymer molecule.

Calculate the mass of this polymer molecule.

Some naturally occurring molecules are polymers.

Draw one straight line from each natural polymer to its monomer.

*(c) Figure 13 shows information about four compounds, E, F, G and H.

The compounds are in no particular order

• butane

• carbon dioxide

• ethane

• ethene.

Use all of the information in Figure 13 to identify which of the four compounds, E, F, G and H, is

• butane

• carbon dioxide

• ethane

• ethene.

You must give reasons for your choices.

Figure 17 shows a poly(ethene) bottle containing substance K with one of its hazard symbols showing.

Explain a safety precaution that should be taken when using a substance with the hazard symbol shown in Figure 17.

Substance K has the formula AgNO₃. Give the name of substance K.

State one property of poly(ethene) that makes it a suitable material to make a container for storing substances.

A student tests a solid for chloride ions.

The student uses the following method.

step 1 dissolve a small amount of the solid in water

step 2 add some dilute hydrochloric acid

step 3 add a few drops of a solution of K

step 4 observe whether or not a white precipitate forms.

This method to show whether the solid contains chloride ions will not work.

Explain a change that needs to be made to step 2 to allow this method to work.

In the test for carbonate ions, the carbonate ions react with an acid.

Sodium carbonate, Na₂CO₃, is reacted with dilute hydrochloric acid.

Complete and balance the equation for this reaction.

Na₂CO₃ + 2HCl _........ +_........ +_........

The carbonate of element X has the formula X₂CO₃. The relative formula mass of this carbonate is 230.

Using this information, calculate the relative atomic mass of X.

(relative atomic masses: C = 12, O = 16)

Figure 6 shows a poly(ethene) bottle containing substance K with one of its hazard symbols showing.

Explain a safety precaution that should be taken when using a substance with the hazard symbol shown in Figure 6.

Substance K has the formula AgNO₃. Give the name of substance K.

State one property of poly(ethene) that makes it a suitable material to make a container for storing substances.

A student tests a solid for chloride ions.

The student uses the following method.

step 1 dissolve a small amount of the solid in water

step 2 add some dilute hydrochloric acid

step 3 add a few drops of a solution of K

step 4 observe whether or not a white precipitate forms.

This method to show whether the solid contains chloride ions will not work.

Explain a change that needs to be made to step 2 to allow this method to work.

In the test for carbonate ions, the carbonate ions react with an acid.

Sodium carbonate, Na₂CO₃, is reacted with dilute hydrochloric acid.

Complete and balance the equation for this reaction.

Na₂CO₃ + 2HCl _........ +_........ +_........

The carbonate of element X has the formula X₂CO₃. The relative formula mass of this carbonate is 230.

Using this information, calculate the relative atomic mass of X.

(relative atomic masses: C = 12, O = 16)

relative atomic mass of X =_........

Atoms, molecules, nanoparticles and protons are types of particle.

List these four types of particle in order of size from smallest to largest.

Nanoparticles have a large surface area to volume ratio.

Figure 7 shows a cube-shaped nanoparticle with sides of 90 nm.

Figure 7

What is 90 nm in metres?

Calculate the simplest surface area to volume ratio for the nanoparticle in Figure 7.

Show your working.

surface area to volume ratio = 1:_........

Figure 8 shows the structure of a molecule of tetrafluoroethene.

Tetrafluoroethene can form the polymer poly(tetrafluoroethene).

Draw a diagram to show the structure of the repeating unit of this polymer.

Poly(tetrafluoroethene) is also known as Teflon^TM.

State one use of poly(tetrafluoroethene) and explain how one of its properties makes it suitable for that use.

use

explanation

Figure 1 shows toothbrushes in a container.

The toothbrush handles are made of plastic (polymer).

Give a reason why plastic is a suitable material to make a toothbrush handle.

Some toothbrush handles are made of wood, not plastic.

Explain a disadvantage of using plastics.

The container is made of a ceramic material.

Which is a property of the ceramic that makes it suitable for the container?

In some countries, toothpastes contain nanoparticles of silver.

Which statement describes the size of a nanoparticle?

Toothpastes contain abrasives and other substances to make them effective.

Figure 2 is a pie chart of the percentage composition by volume of one toothpaste.

Calculate the volume of water in 150 cm³ of this toothpaste.

The structure of one molecule of a compound is shown in Figure 10.

What is the molecular formula of the compound in Figure 10?

The compound in Figure 10 is an unsaturated hydrocarbon.

State why the compound is described as an unsaturated hydrocarbon.

Many molecules of the compound in Figure 10 combine to form substance Y. Figure 11 shows part of a molecule of substance Y.

H H H H H H H H

Figure 11

What type of substance is Y?

One molecule of the compound in Figure 10 has a mass of 6.9810^–23g.

64 800 of these molecules combine to form one molecule of Y.

Calculate the mass of this molecule of Y in g.

*(d) Alkanes can be burned in air. Different products can be formed as the combustion of alkanes can be complete or incomplete.

An investigation was carried out to compare the energy released when the first four alkanes in the homologous series were burned. Equal amounts of these alkanes were burned to heat 100 cm³ of water. The temperature change for each alkane is shown in Figure 12.

Discuss the complete and incomplete combustion of these alkanes and the trend in the energy changes they produced.

You should give word equations in your answer.

This question is about polymers.

State a problem with recycling polymers.

Describe a problem associated with the disposal of polymers.

Poly(chloroethene) is a polymer made from chloroethene. A molecule of chloroethene is shown in Figure 20.

On Figure 20, draw a circle around the functional group in this molecule.

Draw a section of a poly(chloroethene) molecule containing three repeating units, showing all bonds.

What type of polymer is poly(chloroethene)?

Calculate the relative formula mass of a poly(chloroethene) molecule made from 2850 chloroethene molecules, C₂H₃Cl.

(relative atomic masses: H = 1.00, C = 12.0, C l = 35.5)

Give your answer to three significant figures.

Show your working.

relative formula mass =_........

This question is about polymers.

State a problem with recycling polymers.

Describe a problem associated with the disposal of polymers.

Poly(chloroethene) is a polymer made from chloroethene. A molecule of chloroethene is shown in Figure 5.

On Figure 5, draw a circle around the functional group in this molecule.

Draw a section of a poly(chloroethene) molecule containing three repeating units, showing all bonds.

What type of polymer is poly(chloroethene)?

Calculate the relative formula mass of a poly(chloroethene) molecule made from 2850 chloroethene molecules, C₂H₃Cl.

(relative atomic masses: H = 1.00, C = 12.0, C l = 35.5)

Give your answer to three significant figures.

Show your working.

relative formula mass =_........

Ethanol can be produced by the fermentation of glucose solution.

Which of these shows the word equation for the fermentation of glucose solution?

The names and formulae of the first four alcohols in the homologous series of alcohols are given in Figure 12.

Pentanol is the next member of this series. A molecule of pentanol contains five carbon atoms.

Suggest the formula of a molecule of pentanol.

Draw the structure of a molecule of ethanol. Show all bonds.

Ethanol is present in alcoholic drinks, such as wine.

When a bottle of wine is left open some of the ethanol reacts with the oxygen in the air to form ethanoic acid, CH₃COOH, and water.

Complete the equation for this reaction.

Which calculation shows the percentage by mass of hydrogen in ethanoic acid?

(relative atomic mass of hydrogen, H = 1, relative formula mass of ethanoic acid, CH3₃COOH = 60)

*(d) Polymers have many uses. However, the disposal of polymers after use can be a problem. The uses of polymers are related to their properties.

Some uses of three common polymers are given in Figure 13.

Discuss the reasons for using these polymers in the ways shown in Figure 13 and the problems in disposing of these polymers.

Figure 16 shows the structure of a molecule of dichloroethene.

Describe how dichloroethene monomers form a polymer.

Separate samples of dichloroethene and poly(dichloroethene) are shaken with a few drops of bromine water.

What would be seen ?

Dichloroethene is produced from ethene and chlorine.

In the overall reaction, ethene reacts with chlorine and forms dichloroethene and hydrogen chloride.

Complete the balanced equation for the overall reaction.

Poly(dichloroethene) was used to wrap food to keep it fresh.

Explain one property that a plastic food wrapping must have.

An industrial process uses 500 tonnes of dichloroethene. In the process only 96.5% of the dichloroethene molecules react.

Calculate the mass of dichloroethene that has not reacted.

Give your answer to two significant figures.

Figure 2 shows the structure of a molecule of dichloroethene.

Describe how dichloroethene monomers form a polymer.

Separate samples of dichloroethene and poly(dichloroethene) are shaken with a few drops of bromine water.

What would be seen ?

Dichloroethene is produced from ethene and chlorine.

In the overall reaction, ethene reacts with chlorine and forms dichloroethene and hydrogen chloride.

Complete the balanced equation for the overall reaction.

Poly(dichloroethene) was used to wrap food to keep it fresh.

Explain one property that a plastic food wrapping must have.

An industrial process uses 500 tonnes of dichloroethene. In the process only 96.5% of the dichloroethene molecules react.

Calculate the mass of dichloroethene that has not reacted.

Give your answer to two significant figures.

Polymer molecules can be made by joining together large numbers of small molecules called monomers.

Figure 5 shows the names and structures of some polymers and the monomers used to make them.

Complete the table using the information given.

Plastics are polymers.

State two problems caused by the disposal of polymers.

A molecule of propene has the structure shown in Figure 6.

Which of the following shows the structure of part of a poly(propene) molecule?

H H H H H H

Calculate the relative formula mass of the poly(propene) molecule made from joining together 24 600 molecules of propene, C₃H₆. (relative formula mass: C₃H₆ = 42.0)

Give your answer to three significant figures.

(a) Figure 10 shows information about a glass, a ceramic, a polymer and a metal.

*polymers soften, rather than melt, when heated.

Figure 10

Figure 11 shows part of a household wire that connects a kettle to a plug.

Figure 11

Why is this wire made of metal?

Which type of material would be most suitable for the insulation on this household wire?

Explain, using information from Figure 10, why the ceramic is a suitable material to make a cup that will contain a hot drink of tea or coffee.

The structure of a molecule of a polymer is shown in Figure 12.

Complete the structure of a molecule of the monomer used to make this polymer by adding the missing covalent bonds.

*(ii) Poly(ethene) has many uses in everyday life. Large amounts of poly(ethene) are manufactured from ethene produced by cracking fractions obtained from crude oil.

Poly(ethene) is used to make many objects. After use it is necessary to dispose of the large amounts of poly(ethene) in these objects.

Explain some of the problems associated with the manufacture and disposal of poly(ethene).

Figure 4 shows information about a ceramic and a metal.

The ceramic, rather than the metal, is a more suitable material for washbasins.

Give a reason for this, using a property from Figure 4.

Poly(propene) is an example of a polymer.

The structure of a poly(propene) molecule is shown in Figure 5.

This polymer is made from a monomer.

Draw the structure of the monomer molecule showing all covalent bonds.

A layer of poly(chloroethene) (PVC) is used to surround the copper in electrical cables.

Explain why poly(chloroethene) is a suitable material for this purpose.

Some polymers are polyesters.

What type of reaction takes place when polyesters are formed?

The repeating unit in a polyester molecule is shown in Figure 6.

This polymer is made from two different monomers.

Draw a molecule of each monomer showing all covalent bonds.

Give the name or formula of the small molecule formed when the monomer molecules react to form an ester link.