Alkenes

Which of the following statements about vegetable oil and the margarine produced from it is correct?

May/June 2015

Acidified potassium manganate(VII) is used as the test reagent. When this is added to an aqueous solution of compound X, the colour of the test reagent changes from .....1..... . This colour change indicates that X is .....2..... . Which words correctly fill blanks 1 and 2?

May/June 2015

Alkenes form a homologous series of unsaturated hydrocarbons. The table gives information about some alkenes.

May/June 2015

How can alkenes be produced?

May/June 2016

Which of the following statements are true for alkenes but not for alkanes?

May/June 2016

Each compound W, X, Y and Z is either an unbranched alkane or an unbranched alkene. W: $\text{C}_9\text{H}_{18}$ X: $\text{C}_9\text{H}_{20}$ Y: $\text{C}_{10}\text{H}_{20}$ Z: $\text{C}_{10}\text{H}_{22}$ Which two compounds take part in an addition reaction with bromine?

May/June 2017

A compound causes acidified potassium manganate(VII) to lose its colour. Which compound could it be?

May/June 2018

Z is a compound which: - can be made, as the sole other product, when the alkane $\text{C}_8\text{H}_{18}$ is cracked so as to form butane - decolourises bromine water - contains a branched chain. What is the formula of Z?

May/June 2018

A linear alkene, $\text{C}_4\text{H}_8$, reacts with bromine in an addition reaction. What could the structure of the product be?

May/June 2018

Which one of the reactions is an addition reaction?

May/June 2019

Cyclobutane and butene are both examples of hydrocarbons.

May/June 2019

Vegetable oils may be converted into margarine. Which row shows the changes that occur?

May/June 2021

The diagram shows the structure of propenyl ethanoate.

May/June 2021

The reactants and products for two reactions are shown. reaction 1: $\text{C}_3\text{H}_6 + \text{H}_2\text{O} \rightarrow X$ reaction 2: $X + \text{O}_2 \rightarrow \text{CO}_2 + \text{H}_2\text{O}$ Which row gives the correct description of these two reactions?

May/June 2022

When bromine reacts with a hydrocarbon X, just one product is produced. Which compound is X?

May/June 2022

Alkenes form a homologous series of unsaturated hydrocarbons.

May/June 2022

Isoprene is an alkene that occurs commonly in plants. Which properties are shown by isoprene?

May/June 2023

Ethene, but-1-ene and but-2-ene belong to the alkene family. Figure 7.1 shows the displayed formulae for ethene and but-1-ene.

May/June 2023

The flow chart illustrates some reactions of hydrocarbons. Which row is the correct one?

May/June 2025

A molecule of the compound $\text{C}_4\text{H}_6$ is shown. This molecule takes part in two different addition reactions. It reacts by addition with excess bromine and also by addition with steam. One molecule of $\text{C}_4\text{H}_6$ reacts with ......1...... of bromine. When $\text{C}_4\text{H}_6$ reacts with steam, ......2...... is produced. Which words should go in gaps 1 and 2?

May/June 2025

Fig. 8.1 presents the displayed formula for methylbut-2-enoate.

May/June 2025

Fig. 3.1 shows the equation for the reaction of ethene with bromine.

May/June 2025

Which statement concerning the hydrocarbon $\text{C}_2\text{H}_4$ is incorrect?

Oct/Nov 2015

Propene belongs to the alkene family. It may be prepared from a three-carbon alcohol, $\text{C}_3\text{H}_7\text{OH}$, using the apparatus shown. The reaction equation is $\text{C}_3\text{H}_7\text{OH} \rightarrow \text{C}_3\text{H}_6 + \text{H}_2\text{O}$.

Oct/Nov 2015

A learner sets up apparatus to make ethene, $\text{C}_2\text{H}_4$, as shown below.

Oct/Nov 2015

With which substance does ethene react to produce more than one product?

Oct/Nov 2016

Which substance reacts with ethene to produce more than one product?

Oct/Nov 2016

How many of the structures contain an unsaturated hydrocarbon molecule?

Oct/Nov 2016

Which row gives the correct description of alkenes?

Oct/Nov 2017

Cyclopropane changes into propene when heated.

Oct/Nov 2017

Which of the following statements about vegetable oil and the margarine produced from it is correct?

Oct/Nov 2018

Which of the following statements about vegetable oil and the margarine produced from it is correct?

Oct/Nov 2018

When ethene combines with steam to make ethanol, what kind of reaction is this?

Oct/Nov 2018

The displayed structure of fumaric acid is shown.

Oct/Nov 2018

Alkenes make up a homologous series of unsaturated hydrocarbons.

Oct/Nov 2018

When butene reacts with bromine, which compound could be produced?

Oct/Nov 2019

Which row correctly shows the different formulae for ethene and for its homologous series?

Oct/Nov 2019

A student carries out an investigation into the properties of a colourless organic liquid. Which observation indicates that the liquid is unsaturated?

Oct/Nov 2019

When butene reacts with bromine, which compound might be formed?

Oct/Nov 2019

Which statement concerning propene is correct?

Oct/Nov 2019

Which process is used to produce ethanol from ethene?

Oct/Nov 2019

Which statements about alkenes are correct?

Oct/Nov 2020

X is a branched hydrocarbon in which the ratio of carbon atoms to hydrogen atoms is $1:2$. X has a relative molecular mass of $56$. What is X?

Oct/Nov 2020

Which substances have at least one double bond?

Oct/Nov 2020

The hydrocarbon $\text{CH}_3\text{CHCH}_2$ can take part in several chemical reactions. In which reaction is the carbon-to-carbon single bond broken?

Oct/Nov 2020

Hydrocarbon compounds are able to make rings of carbon atoms as well as chains. The structures of two hydrocarbon rings, P and Q, are displayed. Which one of P and Q is unsaturated, and which one reacts with aqueous bromine?

Oct/Nov 2020

Give one additional reason why petroleum companies carry out cracking.

Oct/Nov 2020

The structure of compound X is displayed below. Four claims are given about compound X. 1 X burns in air, producing carbon dioxide and water. 2 X changes bromine water from colourless to brown. 3 X is propene. 4 Reacting X with hydrogen increases the number of $\text{C-C}$ single bonds. Which claims are correct?

Oct/Nov 2021

What kind of reaction occurs when ethene reacts with steam to make ethanol?

Oct/Nov 2021

A hydrocarbon compound Q has the molecular formula $\text{C}_x\text{H}_y$. Q reacts with hydrogen to give one product whose molecular formula is $\text{C}_x\text{H}_{y+2}$. Which statement about Q is correct?

Oct/Nov 2021

Alkenes belong to a homologous series of hydrocarbons.

Oct/Nov 2021

The diagram shows the structure of organic compound T.

Oct/Nov 2021

Alkenes form a homologous series of hydrocarbons.

Oct/Nov 2022

Hydrogen is used as a reactant in both the Haber process and in the addition reaction with alkenes. Which row is the correct one?

Oct/Nov 2023

On Fig. 5.1, circle the functional group that reacts with aqueous bromine.

Oct/Nov 2023

Alkenes react with bromine in an addition reaction to make dibromoalkanes. Which statement is the correct one?

Oct/Nov 2024

This item concerns alkanes and alkenes.

Oct/Nov 2024

The question focuses on alkanes and alkenes.

Oct/Nov 2024

Which compound undergoes an addition reaction with hydrogen?

Oct/Nov 2025

The word equations for two reactions of ethene are given below. Reaction 1: ethene + hydrogen $\rightarrow$ ethane. Reaction 2: ethene + bromine $\rightarrow$ 1,2-dibromoethane. The bond energies for the bonds used in the reactions are listed in the table. What is the value of $(\Delta H_{\text{reaction 1}} - \Delta H_{\text{reaction 2}})$?

Oct/Nov 2025

Which of the following statements about propene is correct?

Oct/Nov 2025

This question concerns the unsaturated hydrocarbon ethyne. Fig. 6.1 gives the displayed formula of ethyne: H-C≡C-H.

Oct/Nov 2025

Ethene is used in the manufacture of ethanol and poly(ethene). Figure 7.1 shows ethene’s displayed formula.

Oct/Nov 2025