Alkenes

Question 1

What is the general formula for alkenes?

Answer 1

The general formula for alkenes is CnH2n.

Question 2

What is the characteristic feature in the structure of alkenes?

Answer 2

All alkenes contain a double carbon bond, which is shown as two lines between two carbon atoms (C=C).

Question 2

What is the functional group in alkenes?

Answer 2

The double carbon bond (C=C) is the functional group in alkenes.

Question 3

How are alkenes named?

Answer 3

Alkenes are named using the same system as alkanes, with the suffix “-ene” instead of “-ane”.

Question 4

Give the name and structure of the first alkene.

Answer 4

The name and structure of the first alkene is ethene, CH2=CH2.

Question 5

Define the term alkene?

Answer 5

An alkene is a hydrocarbon compound containing at least one carbon-carbon double bond.

Question 6

Explain the term double bond?

Answer 6

A double bond is a covalent bond formed by sharing two pairs of electrons between atoms.

Question 7

Explain the functional group?

Answer 7

A functional group is the specific group of atoms responsible for the characteristic chemical reactions of a compound.

Question 8

Explain what is meant by an unsaturated compound?

Answer 8

An unsaturated compound contains double or triple bonds, which can undergo addition reactions.

Question 9

What type of reactions do alkenes undergo?

Answer 9

Alkenes undergo addition reactions, where atoms of a simple molecule add across the C=C double bond.

Question 9

True or False?

Alkenes are less reactive than alkanes due to their double bond.

Answer 9

False.

Alkenes are more reactive than alkanes due to the presence of the carbon-carbon double bond.

Question 10

What is the reaction between bromine and propene an example of?

Answer 10

The reaction between bromine and propene is an example of an addition reaction.

Question 11

How does the bromine water test work?

Answer 11

Bromine water is orange. When added to an alkane, it remains orange. When added to an alkene, the bromine atoms add across the C=C bond, causing the solution to lose its colour.

Question 12

What is the purpose of the bromine water test?

Answer 12

The bromine water test is used to distinguish between alkanes and alkenes.

Question 12

Why do alkenes react differently from alkanes?

Answer 12

Alkenes can react in ways that alkanes cannot due to the presence of the carbon-carbon double bond, which contains an area of high electron density.

Question 13

Explain what is meant by an addition reaction

Answer 13

A chemical reaction in which atoms or groups of atoms are added across a multiple bond, such as a carbon-carbon double bond.

Question 14

What is bromine water?

Answer 14

An orange-coloured solution of bromine dissolved in water, used to test for the presence of alkenes.

Question 15

What is a saturated compound?

Answer 15

A compound containing only single bonds, which cannot undergo addition reactions.

Question 16

What is an unsaturated compound?

Answer 16

An unsaturated compound contains double or triple bonds, which can undergo addition reactions.

Question 17

True or False?

The bromine water test can distinguish between propane and ethanol.

Answer 17

False.

The bromine water test can only distinguish between alkanes and alkenes due to their different reactivity with bromine, so it can’t distinguish between propane and ethanol.