Free-radical substitution

This question is about organic compounds.

Chloroethene (C₂H₃Cl) is a covalent molecule that is used to make poly(chloroethene).

This is the displayed formula of chloroethene.

Draw a dot‑and‑cross diagram of chloroethene.

Show only the outer shell electrons.

Describe, in terms of electrostatic attraction, what is meant by a covalent bond.

Chloroethene is a monomer.

Draw the displayed formula of the repeat unit of poly(chloroethene).

Poly(chloroethene) is non‑biodegradable.

There are two main methods used to dispose of poly(chloroethene).

Describe one problem caused by each method.

An organic compound contains this percentage composition by mass.

C = 22.0% H = 4.6% Br = 73.4%

Calculate the empirical formula of this compound.

Ethane and ethene undergo different types of reaction with bromine.

Describe the differences between these two reactions.

This question is about alkanes and alkenes.

Ethane and ethene each react with bromine, but under different conditions.

Give a reason why ethane does not undergo an addition reaction with bromine.

Complete the equation for the substitution reaction between ethane and bromine, including an essential condition for the reaction.

condition

Give the colour change that occurs when ethene reacts with bromine water.

The diagram shows the displayed formulae of two compounds in the homologous series of alkenes.

Compounds in the same homologous series have the same general formula.

Give two other characteristics of compounds in the same homologous series.

Explain why the alkenes in the diagram are isomers.

Draw the displayed formula of another alkene that is an isomer of these two alkenes.

The reaction used to make poly(ethene) can be represented by this equation.

H H n

Describe the differences between the reactant and the product in this reaction.

Refer to carbon chain length, type of bond and state of matter in your answer.

This question is about methane, CH₄

The diagram shows a Bunsen burner that uses methane.

During combustion, methane reacts with a gas in the air.

Give the name of this gas.

Give the two products of the complete combustion of methane.

During the incomplete combustion of methane, carbon monoxide forms.

Give a reason why carbon monoxide forms during incomplete combustion.

State why carbon monoxide is poisonous.

The equation shows the reaction of methane with bromine.

Give the name of this type of chemical reaction.

This question is about alkanes and alkenes.

The alkane C₄H₁₀ exists as two isomers.

State what is meant by the term isomers.

Draw the displayed formulae for the two isomers of C₄H₁₀

Ethane (C₂H₆) can react with bromine.

State the condition needed for ethane to react with bromine.

Complete the equation for this reaction.

Give the name for this type of reaction.

Explain why ethane is described as a saturated compound.

State what you would observe when ethane and ethene are added separately to two samples of bromine water.

ethane

ethene

Explain why straight‑chain alkenes always have the same empirical formula, but straight‑chain alkanes have different empirical formulae.

Refer to the molecular formulae of the alkanes C₂H₆ and C₄H₁₀ in your answer.

An organic compound has this percentage composition by mass.

C = 19.2 % H = 4.0 % O = 12.8 % Br = 64.0 %

Calculate the empirical formula of this compound.

This question is about alkanes.

An alkane has the structural formula CH₃CH₂CH₂CH₃

Give the missing information for this alkane.

There are two isomers of C₄H₁₀

State what is meant by the term isomers.

Draw the displayed formula of each isomer of C₄H₁₀

Isomer 1
Isomer 2

Methane reacts with bromine to form bromomethane and one other product.

Give the formula of the other product.

What is the name of this type of reaction?

State the condition needed for this reaction to occur.

When ethane (C₂H₆) burns in a plentiful supply of air, carbon dioxide and water are formed.

Give a chemical equation for this reaction.

When the air supply is limited, incomplete combustion occurs.

Explain why a gas formed by incomplete combustion can cause a problem for humans.

Give a reason why compound X is not a hydrocarbon.

Give the letter of the compound that is a saturated hydrocarbon with the empirical formula CH₂

Give the letter of the compound that produces nine moles of water when one mole undergoes complete combustion.

Give the structural formula of compound Y.

Explain why compounds W and Y are isomers.

Compound Z reacts with bromine in the presence of ultraviolet radiation.

Write a chemical equation for this reaction.

What is the name for this type of reaction?

Describe how the combustion of sulfur-free petrol in a car engine produces gases that can cause acid rain.

Do not refer to carbon dioxide in your answer.

This question is about alkanes and alkenes.

The alkane C₅H₁₂ has three isomers.

State what is meant by the term isomers.

Calculate the relative formula mass (M_r) of C₅H₁₂

This is the displayed formula of one of the isomers.

H H H H H

Give the name of this isomer.

Draw the displayed formulae of the other two isomers.

Isomer 1
Isomer 2

Ethane (C₂H₆) and ethene (C₂H₄) both react with bromine.

Describe the differences in the reactions of ethane and ethene with bromine.

Refer to the conditions, the products and the types of reaction involved.

This question is about alkanes.

Which of these is the molecular formula of an alkane?

Which of these has the same empirical formula and molecular formula?

In the presence of ultraviolet radiation, methane reacts with bromine to form bromomethane and hydrogen bromide.

State the name of this type of reaction.

Give a chemical equation for this reaction.

One mole of an alkane burns completely in oxygen.

The equation represents the reaction.

The numbers x, y and z are used to balance the equation.

The complete combustion of one mole of the alkane produces 220 g of carbon dioxide and 108 g of water.

Calculate the values of y and z.

[M_r of CO₂ = 44 M_r of H₂O = 18]

Determine the molecular formula of the alkane and the value of x.

When an alkane burns in a limited supply of air, incomplete combustion occurs.

Explain why incomplete combustion of an alkane could be harmful to humans.

Give the letter of a compound not shown as a displayed formula.

Give the letter of a saturated compound with the general formula C_nH_2n

Name compound E.

Explain why compound A and compound D are isomers.

Compound F reacts with bromine in the presence of ultraviolet radiation.

Complete the equation for the reaction.

Give the name of this type of reaction.

Another compound, G, has this percentage composition by mass.

C = 37.8 % H = 6.3 % C l = 55.9 %

Show by calculation that the empirical formula of compound G is C₂H₄Cl

The relative formula mass (M_r) of G is 127

Determine the molecular formula of G.

Compound E is used to make an addition polymer.

Give one problem caused by the disposal of addition polymers.

This question is about alkenes and alkanes.

Complete the table by giving the missing information about the alkene with the molecular formula C₃H₆

Alkenes are unsaturated compounds.

State what is meant by the term unsaturated.

Describe a test to show that a compound is unsaturated.

When the alkane methane reacts with chlorine, the products are chloromethane (CH₃Cl) and hydrogen chloride gas.

Give a chemical equation for this reaction.

What is the name of this type of reaction?

State the condition needed for this reaction to occur.

When ethane reacts with chlorine, one of the products of the reaction has the formula C₂H₄Cl₂

There are two isomers with this formula.

State what is meant by the term isomers.

Draw the displayed formulae of the two isomers with the formula C₂H₄Cl₂

Chlorine, bromine and iodine are elements in the Periodic Table.

Explain how the position of these elements in the Periodic Table depends on their electronic configurations.

Chlorine reacts with methane to form CH₃Cl and HCl

State the condition necessary for this reaction.

Give the equation for this reaction.

The bonds in a molecule of CH₃Cl are covalent.

Explain, in terms of electrostatic attractions, what is meant by a covalent bond.

CH₃Cl has a simple molecular structure.

Explain why CH₃Cl has a low boiling point.

Graphite is another substance that contains covalent bonds.

The diagram shows the structure of graphite.

Most covalent substances do not conduct electricity.

Explain why graphite is able to conduct electricity.