Home / iGCSE Chemistry (0620) Core:11.3 Fuels: Exam Style Questions Paper 1

iGCSE Chemistry (0620) Core:11.3 Fuels: Exam Style Questions Paper 1

iGCSE Chemistry (0620) Core Paper 1 - All Chapters
Question

Petroleum is an important raw material that is separated into useful products.

Which terms describe petroleum and the method used to separate it?

 descriptionseparation method
A)compoundcracking
B)compoundfractional distillation
C)mixturecracking
D)mixturefractional distillation
▶️ Answer/Explanation
Solution

Ans: D

Petroleum is a complex mixture of hydrocarbons, not a single compound (eliminating A and B). The initial separation is done by fractional distillation, where petroleum is heated and different fractions condense at different temperatures in the fractionating column. Cracking (options A and C) is a later process that breaks down larger molecules into smaller, more useful ones, but it’s not the initial separation method.

Question

Propane, \( C_3H_8 \), is burned in a limited amount of oxygen.

Which equation represents this reaction?

A) \( C_3H_8 + 5O_2 \rightarrow 3CO_2 + 4H_2O \)

B) \( C_3H_8 + 4O_2 \rightarrow 3CO + 4H_2O \)

C) \( C_3H_8 + 4O_2 \rightarrow 3CO_2 + 2H_2O + 2H_2 \)

D) \( 2C_3H_8 + 7O_2 \rightarrow 6CO + 8H_2O \)

▶️ Answer/Explanation
Solution

Ans: D

When propane burns in limited oxygen, incomplete combustion occurs, producing carbon monoxide (CO) instead of carbon dioxide (CO₂).

Option A shows complete combustion, which doesn’t occur with limited oxygen.

Option B is incorrect because it shows 4O₂ but forms CO₂ (should be CO with limited oxygen).

Option C is incorrect because it shows a mixture of CO₂ and H₂, which doesn’t represent typical incomplete combustion products.

Option D correctly shows the incomplete combustion of propane with limited oxygen, producing carbon monoxide and water.

The equation is balanced with 6 carbon atoms, 16 hydrogen atoms, and 14 oxygen atoms on both sides.

Question

Fractional distillation is used to separate petroleum into its fractions.

Which statement about the fractional distillation of petroleum is correct?

A) The kerosene fraction is used as a fuel for ships.
B) The fractions with the highest boiling points are extracted from the top of the fractionating column.
C) The naphtha fraction contains larger hydrocarbon molecules than the lubricating oil fraction.
D) The refinery gas fraction contains hydrocarbon molecules which consist of five atoms.

▶️ Answer/Explanation
Solution

Ans: D

Let’s analyze each option:

A) Incorrect – The fuel for ships is typically the heavier fuel oil fraction, not kerosene.

B) Incorrect – Fractions with higher boiling points condense at the bottom of the column, not the top.

C) Incorrect – Naphtha contains smaller molecules (C5-C10) than lubricating oil (C20-C50).

D) Correct – Refinery gas contains small molecules like methane (CH4), ethane (C2H6), propane (C3H8), and butane (C4H10), which have 5 atoms (e.g., C3H8 has 3+8=11 atoms, so this might be misleading. Actually, the smallest molecules in refinery gas have 5 atoms (CH4 has 5). The answer key indicates D is correct, though the statement isn’t entirely accurate for all components.

Question

The gases produced by a burning fuel are passed through solution Z using the apparatus shown. The fuel contains compounds of sulfur.

Which row identifies solution Z and the result obtained when the fuel contains compounds of sulfur?

▶️Answer/Explanation

Ans:

A

The purpose of passing the gases through the acidified potassium manganate solution is to test for the presence of sulfur-containing compounds in the fuel. Sulfur compounds, such as sulfur dioxide (SO2), can react with the potassium manganate, causing it to change color from purple to colorless or brown. This is a common chemical test for the presence of sulfur-containing compounds in a gas mixture. If sulfur-containing compounds are present in the gases produced during combustion, the purple color of the potassium manganate solution will fade or change, indicating the presence of sulfur compounds in the fuel. The intensity of the color change can also give an idea of the amount of sulfur present.

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