Fuels

A diagram shows a biogas generator. If the gas is collected, it may be burned as a fuel. However, if the gas is released, it acts as an atmospheric pollutant. What gas is it?

May/June 2015

The diagram illustrates the fractionation of petroleum (crude oil). Which row indicates the correct use of the fraction?

May/June 2018

What fraction of petroleum (crude oil) is employed as a fuel in aircraft engines?

May/June 2018

The table gives the energy released when some compounds undergo complete combustion. Which compound gives out the smallest amount of energy when $1\,\text{g}$ is completely burned?

May/June 2019

Which organic compound needs the smallest number of moles of oxygen for the complete combustion of 1 mole of the compound?

May/June 2019

The table gives the energy released when some compounds undergo complete combustion. Which compound gives out the smallest amount of energy when $1\,\text{g}$ is completely burned?

May/June 2019

Which organic compound needs the smallest number of moles of oxygen for the complete combustion of 1 mole of the compound?

May/June 2019

Petroleum (crude oil) is an important source for many chemicals.

May/June 2019

Ethanol is made by fermenting glucose obtained from sugar cane. In some countries, ethanol is used as a fuel. Which statements are correct?

May/June 2021

Natural gas is used as a source of energy. Which compound is the main component of natural gas?

May/June 2021

Ethanol is made by fermenting glucose obtained from sugar cane. In some countries, ethanol is used as a fuel. Which statements are correct?

May/June 2021

Petroleum (crude oil) supplies the starting materials used to produce ethanol and ammonia.

May/June 2021

The table lists some fractions produced by the fractional distillation of petroleum together with their uses. Which rows are correct?

May/June 2023

Fractional distillation is used to separate petroleum into useful products. Which fraction here has the lowest boiling point?

May/June 2024

Petroleum is split into fractions in a fractionating column. Which fraction property becomes greater from the base to the top of the column?

May/June 2025

In one experiment, $1\,\text{cm}^3$ of a gaseous hydrocarbon, $Z$, needs $4\,\text{cm}^3$ of oxygen for complete combustion and produces $3\,\text{cm}^3$ of carbon dioxide. All gas volumes are taken at r.t.p. Which formula shows $Z$?

Oct/Nov 2016

During an experiment, $1\,\text{cm}^3$ of a gaseous hydrocarbon, $Z$, needs $4\,\text{cm}^3$ of oxygen for complete combustion, producing $3\,\text{cm}^3$ of carbon dioxide. Every gas volume is taken at r.t.p. Which formula represents $Z$?

Oct/Nov 2016

An incomplete equation for the reaction of ethyne, $\text{C}_2\text{H}_2$, with oxygen is given below. $2\text{C}_2\text{H}_2(g) + \ldots \text{O}_2(g) \rightarrow \ldots \text{CO}_2(g) + \ldots \text{H}_2\text{O}(g)$ After the equation has been balanced, what should the correct value of $\text{O}_2(g)$ be?

Oct/Nov 2018

Petroleum (crude oil) is a blend of hydrocarbons.

Oct/Nov 2019

Petroleum (crude oil) is split into useful fractions by fractional distillation. The points on the fractionating column where fractions X and Y are taken off are shown. Which statement is correct?

Oct/Nov 2020

When alcohols are burned, heat is given out. A student is investigating how much heat is released as different alcohols burn.

Oct/Nov 2022

Two fractions obtained from the separation of petroleum are the lubricating oil fraction and the kerosene / paraffin fraction. Which statement is correct?

Oct/Nov 2023

In the fractional distillation of petroleum, separate fractions are collected from the top and the bottom of the fractionating column. Compared with the fraction taken from the bottom of the fractionating column, what properties does the fraction from the top have? 1 higher viscosity 2 lower boiling point 3 lower volatility 4 shorter chain length

Oct/Nov 2023

Three statements concerning fuels are given. Which of the statements are correct?

Oct/Nov 2025

Petroleum consists of a mixture of hydrocarbons, and most of these are alkanes.

Oct/Nov 2025

A student is separating petroleum. Fig. 1.1 illustrates how the student has set up the apparatus. Fig. 1.1 labels: thermometer, water out, water in, conical flask, petroleum, heat. Apparatus A is marked on the condenser.

Oct/Nov 2025