6 exam-style questions with full mark schemes and model answers. Write your own answer and the AI examiner marks it against the mark scheme.
Different metals are extracted from their ores in different ways. Iron is extracted by reduction with carbon in a blast furnace, whereas aluminium is extracted by electrolysis of molten aluminium oxide. Both metals are found in ores as metal oxides.
Explain why iron can be extracted by reduction with carbon but aluminium must be extracted by electrolysis. In your answer refer to the reactivity series and to the position of carbon within it, and comment on why the electrolysis method is more expensive.
(6 marks)
Iron is extracted by reducing iron(III) oxide with carbon. The balanced equation is:
2Fe2O3+3C→4Fe+3CO2
A furnace uses 320 g of iron(III) oxide, Fe2O3.
(Relative atomic masses: Fe = 56, O = 16.)
(a) Calculate the relative formula mass (Mr) of iron(III) oxide, Fe2O3, and the number of moles in 320 g. (2 marks)
(b) Using the balanced equation, calculate the maximum mass of iron that could be produced from 320 g of iron(III) oxide. Show your working. (2 marks)
Crude oil is a mixture of hydrocarbons that is separated by fractional distillation. Long-chain hydrocarbons can then be broken down by cracking.
(a) Explain how fractional distillation separates crude oil into different fractions. Refer to boiling points. (2 marks)
(b) State one reason why long-chain hydrocarbons are cracked into shorter ones. (1 mark)
Burning fossil fuels releases gases into the atmosphere. Two important pollutants are carbon monoxide and sulfur dioxide.
(a) State how carbon monoxide is produced when a fuel burns, and state one reason why carbon monoxide is dangerous. (2 marks)
(b) State one environmental problem caused by sulfur dioxide released into the atmosphere. (1 mark)
Carbon dioxide is a greenhouse gas. Increasing the amount of carbon dioxide in the atmosphere is linked to climate change.
Explain how greenhouse gases such as carbon dioxide cause the Earth to become warmer. (2 marks)
The Earth's early atmosphere was very different from the atmosphere today. Today, the most abundant gas in the atmosphere is a gas that makes up about 80% of the air.
Name the gas that is the most abundant in the Earth's atmosphere today. (1 mark)