Properties of small molecules

Alkanes are used as fuels.

Butane is an alkane.

Figure 4 shows butane being used to heat a copper kettle.

The use of butane as a fuel involves a combustion reaction.

What gas in the air does butane react with during combustion?

Why is copper a suitable material for a kettle?

Tick () one box.

Copper can be shaped.

Copper has a low melting point.

Copper reacts with water.

Figure 5 represents a butane molecule.

What is the type of bonding in a butane molecule?

Use Figure 5.

Tick () one box.

Covalent

Ionic

Metallic

What type of structure does butane have?

Use Figure 5.

Tick () one box.

Giant structure

Polymer

Small molecule

Table 2 shows the melting points and boiling points of three alkanes.

Which alkane is a liquid at − 185 °C?

Tick () one box.

Ethane

Propane

Butane

This question is about hydrocarbons.

Hexane (C₆H₁₄) and pentane (C₅H₁₂) are hydrocarbons in the same homologous series.

Give the name of the homologous series that includes hexane and pentane.

Give the general formula of the homologous series that includes hexane and pentane.

Explain why the boiling point of hexane is higher than the boiling point of pentane.

Complete the equation for the cracking of hexane (C₆H₁₄) into ethene and one other molecule.

Methane undergoes complete combustion with oxygen.

Figure 10 represents the equation for the reaction.

Figure 10

The energy released forming the new bonds is 814 kJ/mol greater than the energy needed to break the existing bonds.

Table 4 shows some bond energy values.

Calculate value Y in Table 4.

_ Y = ____________________ kJ/mol

This question is about structure and bonding.

Why can metals be shaped?

Tick (✓) one box.

Different-sized atoms distort the structure.

Layers of atoms slide over each other.

Metallic bonds are weak.

Metals have low melting points.

Explain how metals conduct electricity.

You should answer in terms of electrons.

Figure 9 represents the structure of diamond and of sodium chloride.

Compare the structure and bonding of diamond with the structure and bonding of sodium chloride.

Ethene (C₂H₄) is a small molecule.

Calculate the relative formula mass (M_r) of ethene.

Relative atomic masses (A_r): C = 12 H = 1

Ethene molecules join together to form long-chain poly(ethene) molecules.

Explain why poly(ethene) has a higher melting point than ethene.

You should refer to the:

This question is about structure and bonding.

Why can metals be shaped?

Tick (✓) one box.

Different-sized atoms distort the structure.

Layers of atoms slide over each other.

Metallic bonds are weak.

Metals have low melting points.

Explain how metals conduct electricity.

You should answer in terms of electrons.

Figure 1 represents the structure of diamond and of sodium chloride.

Compare the structure and bonding of diamond with the structure and bonding of sodium chloride.

Ethene (C₂H₄) is a small molecule.

Calculate the relative formula mass (M_r) of ethene.

Relative atomic masses (A_r): C = 12 H = 1

Ethene molecules join together to form long-chain poly(ethene) molecules.

Explain why poly(ethene) has a higher melting point than ethene.

You should refer to the:

This question is about substances found in the Earth’s crust.

Aluminium silicate is a compound found in the Earth’s crust.

The formula of aluminium silicate is Al₂SiO₅

What is the total number of atoms in the formula Al₂SiO₅?

Tick (✓) one box.

3 5 7 8

Table 2 shows the percentage of some elements found in the Earth’s crust.

Calculate the simplest whole number ratio for the percentage of silicon to the percentage of aluminium in the Earth’s crust.

Simplest whole number ratio for: percentage of silicon: percentage of aluminium = _____________: _____________

Iron is found as iron oxide in the Earth’s crust.

Iron can be extracted by heating iron oxide with carbon.

Why is iron oxide reacted with carbon to extract iron?

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Iron is less reactive than carbon.

Iron has the same reactivity as carbon.

Iron is more reactive than carbon.

The word equation for the reaction to extract iron is:

iron oxide + carbon iron + carbon dioxide

Which reactant is reduced?

Tick (✓) one box.

Carbon

Carbon dioxide

Iron

Iron oxide

The symbol equation for the reaction to extract iron is:

What is the value of X ?

Tick (✓) one box.

2 3 4 5

Aluminium is found as aluminium oxide in the Earth’s crust.

Figure 8 shows the apparatus used for the process to extract aluminium from aluminium oxide.

Name the process used to extract aluminium from aluminium oxide.

What are the positive electrodes made of in this process?

Tick (✓) one box.

Aluminium

Carbon

Copper

Cryolite

Large amounts of energy are used in the process in Figure 8.

Give two ways energy is used in the process.

Diamond and silicon dioxide are also found in the Earth’s crust.

Figure 9 represents the structure of diamond and the structure of silicon dioxide.

Compare the structure and bonding of diamond with the structure and bonding of silicon dioxide.

This question is about polymers and plastics.

Figure 12 shows the displayed formula for poly(chloroethene).

What does ‘n’ represent in the displayed formula for poly(chloroethene)?

The representation of poly(chloroethene) in Figure 12 does not show the actual structure of the molecule.

Give one reason why.

Poly(chloroethene) is commonly known as PVC.

PVC does not decompose in the ground.

Many polymer plastics like PVC become pollutant waste in the oceans.

In the oceans, PVC can break into smaller pieces.

The smaller pieces are called PVC nanoplastic.

A piece of PVC nanoplastic has a thickness of 50 nm

Calculate the thickness of the PVC nanoplastic in metres.

Give your answer in standard form.

1 nm = 0.000 000 001 m

Suggest two reasons why PVC nanoplastic can be harmful to marine life.

Suggest two ways to reduce plastic waste.

This question is about polymers and plastics.

Figure 1 shows the displayed formula for poly(chloroethene).

What does ‘n’ represent in the displayed formula for poly(chloroethene)?

The representation of poly(chloroethene) in Figure 1 does not show the actual structure of the molecule.

Give one reason why.

Poly(chloroethene) is commonly known as PVC.

PVC does not decompose in the ground.

Many polymer plastics like PVC become pollutant waste in the oceans.

In the oceans, PVC can break into smaller pieces.

The smaller pieces are called PVC nanoplastic.

A piece of PVC nanoplastic has a thickness of 50 nm

Calculate the thickness of the PVC nanoplastic in metres.

Give your answer in standard form.

1 nm = 0.000 000 001 m

Suggest two reasons why PVC nanoplastic can be harmful to marine life.

Suggest two ways to reduce plastic waste.

This question is about hydrogen chloride.

A hydrogen atom contains 1 electron and a chlorine atom contains 17 electrons.

Complete Figure 1 to show a dot and cross diagram for a hydrogen chloride molecule.

Show the outer electrons only.

Hydrogen gas (H₂) reacts with chlorine gas to produce hydrogen chloride.

Complete the balanced chemical equation for the reaction between hydrogen and chlorine.

Figure 2 shows the reaction profile diagram for the reaction between hydrogen and chlorine.

What do A and B represent on Figure 2 ?

How does the reaction profile diagram show that the reaction is exothermic?

Hydrogen chloride gas dissolves in water to form hydrochloric acid.

Hydrochloric acid contains hydrogen ions and chloride ions.

Explain why hydrogen chloride gas does not conduct electricity but hydrochloric acid is able to conduct electricity.