Question 1: Cracking is a process used in the oil industry to break down large hydrocarbon molecules into smaller, more useful ones. It involves the use of heat and catalysts to produce alkenes and shorter-chain alkanes.

Answer: Cracking breaks large hydrocarbons into smaller ones using heat and catalysts, producing alkenes and shorter alkanes.

Question 1: Define 'cracking' in the context of organic chemistry and crude oil processing.

Answer: Cracking is the process of breaking down large hydrocarbon molecules into smaller, more useful molecules such as alkenes and alkanes.

Question 2: Explain the difference between thermal cracking and catalytic cracking.

Answer: Thermal cracking uses high heat and pressure without a catalyst, producing alkenes; catalytic cracking uses a catalyst to lower energy requirements and produces branched alkanes and aromatic compounds.

Question 1: A large hydrocarbon molecule with a molecular formula of C16H34 undergoes cracking to produce smaller hydrocarbons. If 0.5 mol of C16H34 is cracked, how many moles of C2H4 (ethene) can potentially be produced if all the carbon atoms are converted into ethene molecules?

Answer: 16 mol of C2H4

Question 2: Calculate the volume of ethene gas (at room temperature and pressure, 24°C and 1 atm) produced from cracking 2 mol of C16H34, assuming complete conversion and ideal gas behaviour. (Use 24.4 L/mol for molar volume).

Answer: 48.8 L

Question 1: Describe the main safety precautions that should be taken during industrial cracking processes.

Answer: Safety precautions include controlling temperature and pressure, using proper protective equipment, ensuring good ventilation, and handling catalysts carefully to prevent accidents.

Question 2: Identify two products obtained from cracking that are important in the production of plastics and explain their uses.

Answer: Ethene and propene are produced from cracking; they are used as monomers in manufacturing plastics like polyethylene and polypropylene.

Question 1: In a refinery, the percentage yield of ethene from cracking a batch of C16H34 is 85%. If 10 mol of C16H34 is cracked, how many moles of ethene are produced?

Answer: 8.5 mol

Question 2: Discuss how cracking contributes to the supply of useful hydrocarbons in the context of modern industry and everyday life.

Answer: Cracking allows the conversion of large, less useful hydrocarbons into smaller, more valuable ones like ethene and propene, which are essential for producing plastics, fuels, and chemicals. It helps meet the high demand for these products and reduces waste of heavier hydrocarbons in crude oil.