Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Organic Chemistry
785 practice questions
Topics covered
Practice questions
121–130 of 335 · Normal
Question 121
6 marks · Normal
Answer and see the solution →Crude oil is separated into different fractions in an oil refinery. Some of these fractions are used as fuels in daily life.
(a)[2 marks]Describe briefly how crude oil is separated into fractions in a refinery.
(b)[2 marks]Name two main fractions obtained from fractional distillation and state one typical use for each.
(c)[1 mark]Refinery gases are an important by-product at a refinery. State one use of refinery gases.
(d)[1 mark]Give the main use of gasoline in modern society.
Question 122
6 marks · Normal
Answer and see the solution →Combustion reactions of hydrocarbons from different fractions have important uses.
(a)[1 mark]State two products formed when a hydrocarbon fuel undergoes complete combustion.
(b)[1 mark]Write a word or symbol equation for the complete combustion of methane.
(c)[2 marks]Explain why carbon monoxide is formed during incomplete combustion of hydrocarbons and why it is dangerous.
(d)[2 marks]Gasoline is commonly used as a fuel in cars. Explain why gasoline is suitable for this use.
Question 123
6 marks · Normal
Answer and see the solution →The properties and uses of fuels produced from crude oil can affect both technology and human health.
(a)[3 marks]Explain why incomplete combustion of fuels can be more harmful to health than complete combustion.
(b)[2 marks]Suggest one reason why gasoline is preferred over diesel or kerosene as a fuel for most cars.
(c)[1 mark]Apart from car fuel, state one other use of the gasoline fraction.
Question 124
6 marks · Normal
Answer and see the solution →Crude oil is separated into fractions by fractional distillation in an oil refinery. The lowest boiling point fraction is 'refinery gases', which contains a mixture of small hydrocarbons. Some of these gases are used domestically as liquefied petroleum gas (LPG).
Gasoline, another fraction, is mainly used as a fuel in cars.
(a)[2 marks]A refinery processes 50 tonnes of crude oil and produces 3 tonnes of refinery gases. Calculate the percentage by mass of refinery gases obtained from the crude oil. Give your answer to two significant figures.
(b)[4 marks]A house uses 18 kg of refinery gases (LPG) per week for heating and cooking.
Assuming the refinery gases produced in part (a) are supplied entirely for use as LPG, calculate the maximum number of houses that could be supplied for 1 year. (Take 1 year = 52 weeks).
Question 125
2 marks · Normal
Answer and see the solution →State the general formula of alkanes and explain what this formula represents.
Question 126
4 marks · Normal
Answer and see the solution →The alkane with six carbon atoms is called hexane.
(a)[1 mark]Write the molecular formula for hexane.
(b)[2 marks]Draw the displayed (structural) formula of hexane.
(c)[1 mark]Give the name of the alkane with three carbon atoms in a straight chain.
Question 127
3 marks · Normal
Answer and see the solution →Octane (C8H18) can undergo substitution with chlorine in the presence of UV light.
Write the balanced chemical equation for the mono-substitution reaction of octane with chlorine. Give the formulae for all reactants and products. Calculate the total number of hydrogen atoms remaining in all the organic product molecules if 5 moles of octane completely undergo mono-substitution.
Question 128
3 marks · Normal
Answer and see the solution →Explain why alkanes have the general formula CnH2n+2, making reference to the bonding and structure of these molecules.
Question 129
4 marks · Normal
Answer and see the solution →The table below shows the number of carbon and hydrogen atoms in three different unbranched alkanes.
Alkane Number of carbon atoms Number of hydrogen atoms Methane 1 4 Butane 4 10 Nonane 9 20 (a)[2 marks]Using the data, deduce the general formula connecting the number of hydrogen atoms (H) to the number of carbon atoms (C) in alkanes.
(b)[1 mark]Predict the number of hydrogen atoms in a straight-chain alkane with 7 carbon atoms.
(c)[1 mark]Name the alkane with 9 carbon atoms.
Question 130
1 mark · Normal
Answer and check →What is required for a substitution reaction between ethane and chlorine to take place?
- A.High pressure
- B.A catalyst
- C.Ultraviolet light
- D.Heating to 1000°C