Alkanes as fuels and pollutionEdexcel A-Level Chemistry: Flashcards
What these 14 flashcards ask
- What is the general formula of alkanes?
- What is the general formula of cycloalkanes?
- What does saturated mean for a hydrocarbon?
- How does fractional distillation separate crude oil?
- Why is cracking carried out?
- What is reforming and why is it done?
- What are the products of incomplete combustion of an alkane?
- Why is carbon monoxide toxic?
- How do oxides of nitrogen form in an engine?
- Why do oxides of nitrogen and sulfur cause problems?
- Write the equation for the main reaction in a catalytic converter.
- Which metals are used in a catalytic converter?
- Why are biodiesel and ethanol renewable?
- Give one disadvantage of fuels made from plants.
Exam questions on Alkanes as fuels and pollution
- A refinery separates crude oil by fractional distillation. One fraction contains mainly heptane, C₇H₁₆, a straight-chain alkane. Part of this fraction is processed further so that it can be blended into petrol for use in car engines.Explain why the refinery reforms some of the straight-chain alkanes in this fraction before blending them into petrol.2 marks
- A petrol car is driven on a motorway. Air enters the engine and the fuel burns at a very high temperature in a limited supply of oxygen, so the exhaust gases contain carbon monoxide, nitrogen monoxide, unburned hydrocarbons and carbon particulates before they pass through the exhaust system.Write an equation for the formation of nitrogen monoxide in the engine and explain why it forms in the engine but not in the cold air outside the car.2 marks
- The exhaust system of the car contains a catalytic converter. This is a honeycomb of ceramic coated with a thin layer of platinum, palladium and rhodium. The exhaust gases pass through it before leaving the car.The converter helps to solve two pollution problems when carbon monoxide reacts with nitrogen monoxide. Write an equation for this reaction and explain how it reduces each problem.3 marks
Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).