WAEC Chemistry 2019 Theory — Question 1
Question 1 of 28 from the West African Examinations Council (WAEC) Chemistry 2019 Theory paper, with the correct answer and a full explanation.
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1(a) State the conditions necessary for the cracking of long-chain hydrocarbons to produce more gasoline. [2 marks]
Model answer
There are two types of cracking: • Thermal cracking: large hydrocarbons are broken into smaller ones using a high temperature of about 450–750°C and a pressure of about 70 atmospheres. • Catalytic cracking: the hydrocarbon is brought into contact with a catalyst (commonly a zeolite) at about 500°C and a moderately low pressure.
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