Alkenes

Which kind of hydrocarbon reacts quickly with aqueous bromine, and what colour change does the aqueous bromine undergo?

Feb/March 2017

Which reaction involving ethene is not classified as an addition reaction?

Feb/March 2017

Which molecular formula is that of an alkene?

Feb/March 2018

Three chemical reactions are depicted. 1. catalytic addition of steam to ethene 2. combustion of ethanol 3. fermentation of glucose In which of these reactions does the relative molecular mass of the carbon-containing compound fall?

Feb/March 2018

What process is used to produce an alkene from a long-chain alkane?

Feb/March 2019

Which of the following statements about propene are correct?

Feb/March 2020

Which of the following statements about propene are correct?

Feb/March 2020

Pentane is an alkane, whereas pentene is an alkene. What is seen when bromine water is added to a sample of each compound?

Feb/March 2021

Which statement describes how ethene reacts with steam?

Feb/March 2021

The table lists the names or structures of organic compounds P to U.

Feb/March 2021

What is the structural formula of the compound made when propene undergoes an addition reaction with bromine?

Feb/March 2023

Which formula shows an unsaturated hydrocarbon?

Feb/March 2024

Which of the following statements about the reaction between ethene and steam are correct?

Feb/March 2024

Alkenes form a homologous series of hydrocarbons produced when larger alkane molecules are cracked.

Feb/March 2024

At room temperature and pressure, both butane and but-1-ene are colourless gases.

Feb/March 2024

Which of the following statements about alkenes is correct?

Feb/March 2025

Two compounds, A and B, have the structural formulae shown below. A: CH₂=CHCH₃ B: CH₃CH=CHCH₃ A and B belong to one homologous series.

Feb/March 2025

Compound Q turns bromine water colourless. Each molecule of compound Q contains two carbon atoms. Which statement about compound Q is correct?

May/June 2016

A hydrocarbon W undergoes combustion to produce carbon dioxide and water. W also decolourises bromine water. What is the name of W, and what does its structure look like?

May/June 2016

What reaction is used to test for alkenes?

May/June 2016

The diagrams of six organic compounds are displayed and labelled A, B, C, D, E and F.

May/June 2016

Which compound makes aqueous bromine decolourise rapidly?

May/June 2017

Two chemical reactions are displayed. 1 butane $\rightarrow$ ethene 2 ethene $\rightarrow$ ethanol Which terms are used to describe reactions 1 and 2?

May/June 2017

Ethene is a hydrocarbon. Which row gives the kind of bond linking the carbon atoms in ethene, and the effect of ethene on aqueous bromine?

May/June 2017

Poly(ethene) is formed from ethene. Ethene is a .....1..... hydrocarbon because it has a carbon to carbon .....2..... bond. The general term for small molecules that polymerise is .....3..... . Which words fill gaps 1, 2 and 3?

May/June 2017

Which substances may be produced when hydrocarbons are cracked?

May/June 2018

Which substances may be made by cracking hydrocarbons?

May/June 2018

Which reaction is not one that alkenes undergo?

May/June 2018

Which of the following statements about alkenes is incorrect?

May/June 2018

Which substances are produced by cracking hydrocarbons?

May/June 2018

The table presents the structures of four hydrocarbons.

May/June 2018

A hydrocarbon W burns to produce carbon dioxide and water. W decolourises bromine water. What is the identity of W, and what does its structure look like?

May/June 2019

A hydrocarbon W burns to produce carbon dioxide and water. W decolourises bromine water. What is W called, and what does its structure look like?

May/June 2019

Hydrocarbon W burns, producing carbon dioxide and water. W makes bromine water lose its colour. What is W called, and what is its structure?

May/June 2019

Coal gas is produced when coal is heated without air present. The chief gases in coal gas are listed below: carbon dioxide carbon monoxide ethene hydrogen methane nitrogen

May/June 2019

The structures of five alkenes, A, B, C, D and E, are displayed.

May/June 2019

Why can these two compounds be classified as hydrocarbons?

May/June 2019

There are four organic compounds, P, Q, R and S. P is classed as an unsaturated hydrocarbon. Q burns, but is otherwise unreactive. R has a $\text{C--C}$ single bond together with a $\text{C{=}C}$ double bond. S undergoes addition polymerisation. Which of the compounds are alkenes?

May/June 2021

Which compound causes aqueous bromine to become decolourised?

May/June 2021

P, Q, R and S are four organic compounds. P is an unsaturated hydrocarbon. Q combusts but is otherwise unreactive. R has a $\text{C-C}$ single bond and a $\text{C=C}$ double bond. S undergoes addition polymerisation. Which of the compounds are alkenes?

May/June 2021

What quantity of hydrogen is required to react fully with $0.02$ moles of butene in order to form butane?

May/June 2021

A large number of organic compounds consist solely of carbon, hydrogen and oxygen.

May/June 2021

The equation for the reaction between a hydrocarbon and water is shown below. $\mathrm{C}_x\mathrm{H}_y + \mathrm{H}_2\mathrm{O} \xrightarrow{\text{catalyst}} \mathrm{C}_x\mathrm{H}_5\mathrm{OH}$ What are the values of $x$ and $y$?

May/June 2022

Ethene reacts with substance X to produce ethanol. What is X?

May/June 2022

Alkenes may be formed when cracking breaks large hydrocarbon molecules into smaller hydrocarbon molecules. Which equations show possible reactions when tetradecane, $\text{C}_{14}\text{H}_{30}$, is cracked?

May/June 2022

A hydrocarbon is examined using aqueous bromine. The aqueous bromine changes from orange to colourless. Which row gives the description of the hydrocarbon?

May/June 2022

A molecule of compound P has two carbon atoms and four hydrogen atoms. Which row shows P?

May/June 2022

If ethene reacts with substance X and ethanol is formed, what is X?

May/June 2022

Alkenes may be formed by cracking large hydrocarbon molecules into smaller hydrocarbon molecules. Which equations show possible reactions when tetradecane, $\text{C}_{14}\text{H}_{30}$, is cracked?

May/June 2022

Butene has three structural isomers that are alkenes. Which of these statements about the isomers are correct?

May/June 2022

Which compound causes aqueous bromine to lose its colour quickly?

May/June 2023

Hydrocarbon P undergoes cracking to produce compound Q and hydrogen. Compound R is made by the addition polymerisation of compound Q. Which homologous series do P, Q and R each belong to?

May/June 2023

What structure is formed by the product when propene reacts with bromine?

May/June 2023

The hydrocarbon $\text{C}_4\text{H}_8$ exists as two structural isomers, but-1-ene and but-2-ene. Which statement is correct?

May/June 2023

Which compound makes aqueous bromine lose its colour rapidly?

May/June 2023

What products are formed when ethene undergoes addition reactions with bromine and hydrogen?

May/June 2023

Some symbol equations and word equations, A to J, are given below. A $\text{H}^+ + \text{OH}^- \rightarrow \text{H}_2\text{O}$ B $\text{Cr}^{3+} + 3\text{OH}^- \rightarrow \text{Cr(OH)}_3$ C methane + chlorine → chloromethane + hydrogen chloride D propene + bromine → 1,2-dibromopropane E $\text{C}_{10}\text{H}_{22} \rightarrow \text{C}_8\text{H}_{18} + \text{C}_2\text{H}_4$ F chlorine + aqueous potassium bromide → bromine + aqueous potassium chloride G methane + oxygen → carbon monoxide + water H $\text{C}_2\text{H}_5\text{COOH} + \text{CH}_3\text{OH} \rightarrow \text{C}_2\text{H}_5\text{COOCH}_3 + \text{H}_2\text{O}$ I hydrogen + oxygen → water J $6\text{CO}_2 + 6\text{H}_2\text{O} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2$ Work through the equations to answer the questions that come next. Each equation may be chosen once, used more than once, or not chosen at all. Write the letter, A to J, for the equation that shows:

May/June 2023

Which statements about propene are correct?

May/June 2024

An equation for a reaction that makes ethanol is given: ethene + steam $\rightarrow$ ethanol. Which type of reaction does the equation represent?

May/June 2024

Four statements concerning ethene or poly(ethene) are given. Which of the statements are correct?

May/June 2024

Which molecular formula corresponds to an alkene?

May/June 2024

Bromine water is placed into two test-tubes. Extra hexene is then put into the first test-tube. Extra hexane is then put into the second test-tube. Which row shows the observation for each test-tube?

May/June 2024

Which formula shows an alkene?

May/June 2024

Alkenes undergo an addition reaction with steam. Certain alkenes form just one alcohol product. Certain alkenes form two different alcohols that are structural isomers. Which row shows the number of alcohol isomers produced when ethene reacts with steam and when propene reacts with steam?

May/June 2024

Certain plants give off ethene gas.

May/June 2024

A list of words used to describe organic compounds is shown. Which of these words describe ethene?

May/June 2025

Three hydrocarbons are each mixed separately with aqueous bromine. Which row shows the correct observation for every hydrocarbon?

May/June 2025

Ethene, $\text{C}_2\text{H}_4$, is the first member of a set of closely related compounds that possesses the alkene functional group.

May/June 2025

Which compound does not belong to the alkene homologous series?

Oct/Nov 2016

Which compound turns aqueous bromine colourless?

Oct/Nov 2016

An organic compound has these properties. colour: colourless action on Universal Indicator: none flammability: highly flammable action on aqueous bromine: decolourises state at room temperature: gas Which homologous series does this organic compound belong to?

Oct/Nov 2016

Butane reacts as shown. $\text{butane} \xrightarrow[\text{and heat}]{\text{catalyst}} \text{butene} + \text{hydrogen}$ What type of reaction is this?

Oct/Nov 2016

Butane changes according to the equation shown: butane $\xrightarrow[\text{and heat}]{\text{catalyst}}$ butene + hydrogen. What type of reaction is this?

Oct/Nov 2016

Fractional distillation can be used to split petroleum into useful hydrocarbon fractions.

Oct/Nov 2016

X, Y and Z are three hydrocarbons. $X$: $\text{CH}_2{=}\text{CH}_2$, $Y$: $\text{CH}_3{-}\text{CH}{=}\text{CH}_2$, $Z$: $\text{CH}_3{-}\text{CH}_2{-}\text{CH}{=}\text{CH}_2$. What feature do compounds X, Y and Z all share?

Oct/Nov 2017

The displayed structures represent four organic compounds. Which of the compounds are unsaturated?

Oct/Nov 2017

X, Y and Z are three hydrocarbons made up only of carbon and hydrogen. X: $\text{CH}_2=\text{CH}_2$ Y: $\text{CH}_3-\text{CH}=\text{CH}_2$ Z: $\text{CH}_3-\text{CH}_2-\text{CH}=\text{CH}_2$ What feature is shared by compounds X, Y and Z?

Oct/Nov 2017

X, Y and Z are three different hydrocarbons. $X\ \ \text{CH}_2{=}\text{CH}_2$ $Y\ \ \text{CH}_3{-}\text{CH}{=}\text{CH}_2$ $Z\ \ \text{CH}_3{-}\text{CH}_2{-}\text{CH}{=}\text{CH}_2$ Which feature do compounds X, Y and Z share?

Oct/Nov 2017

X, Y and Z are three hydrocarbons. $X$: $\text{CH}_2=\text{CH}_2$\quad $Y$: $\text{CH}_3-\text{CH}=\text{CH}_2$\quad $Z$: $\text{CH}_3-\text{CH}_2-\text{CH}=\text{CH}_2$ What feature do compounds X, Y and Z all share?

Oct/Nov 2017

Structures of four organic compounds are shown. Which of the compounds are unsaturated?

Oct/Nov 2017

X, Y and Z are three hydrocarbons. $\text{X: CH}_2=\text{CH}_2$, $\text{Y: CH}_3-\text{CH}=\text{CH}_2$, $\text{Z: CH}_3-\text{CH}_2-\text{CH}=\text{CH}_2$ What feature do compounds X, Y and Z share?

Oct/Nov 2017

The hydrocarbons X, Y and Z are shown below. X: $\text{CH}_2=\text{CH}_2$ Y: $\text{CH}_3-\text{CH}=\text{CH}_2$ Z: $\text{CH}_3-\text{CH}_2-\text{CH}=\text{CH}_2$ What feature do compounds X, Y and Z share?

Oct/Nov 2017

The diagram presents a reaction pathway. butane $\xrightarrow{X}$ ethene $\xrightarrow{Y}$ ethanol $\xrightarrow{Z}$ carbon dioxide and water Which row gives the names of the processes X, Y and Z?

Oct/Nov 2017

Alkanes and alkenes form two homologous series within hydrocarbons.

Oct/Nov 2017

Which two compounds are molecules that both contain a double bond?

Oct/Nov 2018

Which pair of compounds are molecules, and each contains a double bond?

Oct/Nov 2018

Which statement concerning alkenes is correct?

Oct/Nov 2020

Propene is an alkene that undergoes reactions with bromine, steam and hydrogen, as illustrated below. What products are formed in these reactions?

Oct/Nov 2020

Which molecule is not formed by an addition reaction of ethene?

Oct/Nov 2020

Which product is formed when bromine reacts with propene, $\text{CH}_3\text{CH=}\text{CH}_2$?

Oct/Nov 2020

Ethene belongs to the alkene family.

Oct/Nov 2020

Crotonic acid is displayed in structural form.

Oct/Nov 2020

Alkenes and alkanes are two homologous series of compounds that contain carbon and hydrogen atoms.

Oct/Nov 2020

Which of the following statements about ethene are correct?

Oct/Nov 2021

Which of these statements about unsaturated hydrocarbons are correct?

Oct/Nov 2021

Ethanol is made by reacting compound P with steam in the presence of a catalyst. What is P?

Oct/Nov 2021

Propene undergoes a reaction with steam to produce propanol. $\text{C}_3\text{H}_6(g) + \text{H}_2\text{O}(g) \rightarrow \text{C}_3\text{H}_7\text{OH}(g)$. What kind of reaction is this?

Oct/Nov 2021

Which of the following statements about ethene is correct?

Oct/Nov 2021

Which of these statements about unsaturated hydrocarbons is correct?

Oct/Nov 2021

Some reactions involving substance Q are shown. Ethanol is produced when steam is reacted under pressure with a catalyst. $\text{Q} + \text{Br}_2 \rightarrow$ 1,2-dibromoethane is made. $\text{Q} + \text{H}_2 \rightarrow \text{P}$ (with a catalyst) What substance is P?

Oct/Nov 2021