CIE iGCSE Co-Ordinated Science C11.3 Fuels Exam Style Questions Paper 1
▶️ Answer/Explanation
The main constituent of natural gas is methane, which has the molecular formula \(\mathrm{CH_4}\). Methane is the simplest alkane with a single carbon atom bonded to four hydrogen atoms. Options A and B show butane (4 carbons), while option C shows ethane (2 carbons). Only option D shows the correct displayed formula for methane.
✅ Answer: (D)
✅ Answer: (D)
▶️ Answer/Explanation
Fractional distillation separates the different fractions of petroleum based on their boiling points. As the mixture is heated, substances with lower boiling points evaporate and rise to the top of the fractionating column, while those with higher boiling points condense lower down. This separation relies on the differences in boiling points of the hydrocarbon fractions.
✅ Answer: (A)
✅ Answer: (A)
▶️ Answer/Explanation
Naphtha is a fraction obtained from the fractional distillation of petroleum. It is used as a chemical feedstock to produce other chemicals such as plastics and synthetic fibres. Cooking gas and heating use other fractions, while bitumen is used for roads.
✅ Answer: (D)
✅ Answer: (D)
▶️ Answer/Explanation
The main constituent of natural gas is methane, not ethane. Naphtha is used as a chemical feedstock, not for heating and cooking (refinery gas is used for that). Petroleum itself is the crude oil mixture; the gasoline/petrol fraction is used as fuel in car engines. Gas oil (diesel oil) is correctly identified as fuel for diesel engines.
✅ Answer: (B)
✅ Answer: (B)
▶️ Answer/Explanation
Petroleum is a mixture of hydrocarbons with different boiling points. Fractional distillation separates them into fractions, including gasoline (petrol). Crystallisation, chromatography and filtration are used for other types of mixtures, not for separating petroleum fractions.
✅ Answer: (D)
✅ Answer: (D)