CIE iGCSE Co-Ordinated Science C10.2 Air quality and climate Exam Style Questions Paper 4
Question
Some cars use petrol as a fuel. Some cars use diesel as a fuel.
Table 8.1 shows the mass of pollutant made when 1 kg of petrol or 1 kg of diesel is burnt in a car engine.
(a) (i) Car A uses 5 kg of petrol fuel for a journey. Car B uses 8 kg of diesel fuel for the same journey. State which car, A or B, makes the most nitrogen monoxide. Explain your answer.
▶️Answer/Explanation
Car A makes the most nitrogen monoxide because it uses petrol, which produces more nitrogen monoxide per kg of fuel burned compared to diesel.
Explanation: Car A uses petrol, which produces 59 g of nitrogen monoxide per kg of fuel burned. Car B uses diesel, which produces 29 g of nitrogen monoxide per kg of fuel burned. Therefore, Car A produces 5 × 59 = 295 g of nitrogen monoxide, while Car B produces 8 × 29 = 232 g of nitrogen monoxide.
(a) (ii) The nitrogen monoxide, NO, made inside the car engine is removed by a catalytic converter. The nitrogen monoxide is turned into nitrogen gas and oxygen gas. Construct the balanced symbol equation for this reaction.
▶️Answer/Explanation
The balanced symbol equation for the reaction is 2NO → N2 + O2.
(a) (iii) Sulfur dioxide is a pollutant that causes acid rain. Sulfur dioxide is not removed from car emissions by a catalytic converter. Describe one way that emissions of sulfur dioxide by cars can be reduced.
▶️Answer/Explanation
Using low-sulfur fuel reduces the amount of sulfur dioxide produced during combustion, thereby reducing emissions.
8 (b) A petrol car makes 236 g of carbon monoxide gas when 1 kg of petrol is burnt. Calculate the volume occupied by 236 g of carbon monoxide gas. The molar gas volume at room temperature and pressure is 24 dm3. Show your working.
▶️Answer/Explanation
The volume occupied by 236 g of carbon monoxide gas is 202 dm3.
Explanation:
Molar mass of CO = 12 + 16 = 28 g/mol
Moles of CO = 236 g / 28 g/mol = 8.43 mol
Volume of CO = 8.43 mol × 24 dm3/mol = 202 dm3
8 (c) Sulfur dioxide is used in the manufacture of sulfuric acid in the Contact process.
2SO2(g) + O2(g) ⇌ 2SO3(g)
Describe two conditions used for this reversible reaction. (Sub-topic – C6.3)
▶️Answer/Explanation
Two conditions used for the reversible reaction in the Contact process are a temperature of around 450°C and the use of a vanadium(V) oxide catalyst.
Explanation:
1. Temperature: The reaction is carried out at a temperature of around 450°C.
2. Catalyst: A vanadium(V) oxide (V2O5) catalyst is used to increase the rate of reaction.