7.2 Reactions of alkenes and alcohols

Question 1

What is the general formula for an alkene?

Answer 1

C_nH_2n

Question 2

Why are alkenes described as unsaturated?

Answer 2

They include at least one double covalent bond (between carbons)

Question 3

Name the first four alkenes.

Answer 3

• Ethene
• Propene
• Butene
• Pentene

Question 4

Draw butene.

Answer 4

• 1 single and double covalent bond between 3 carbon atoms.
• Hydrogen atoms bonded with each carbon except double covalent bonded ones (only have 1 carbon bonded to each)

Question 5

What is the functional group of alkenes?

Answer 5

C=C

Question 6

What do alkenes make when they react with oxygen?

Answer 6

Combusts to produce carbon dioxide and water (burn with a smoky flame)

Question 7

What do alkenes make when they react with hydrogen?

Answer 7

Alkanes

Question 8

What do alkenes make when they react with steam?

Answer 8

Alcohols

Question 9

What do alkenes make when they react with chlorine?

Answer 9

Chloroalkanes (Haloalkanes)

Question 10

Draw the product when propene reacts with bromine.

Answer 10

• 3 carbon atoms with single covalent bonds.
• Single bonds with hydrogen and 2 bromine atoms with the old covalently bonded carbons.

Question 11

What is the functional group of an alcohol?

Answer 11

-OH

Question 12

Name the first four alcohols.

Answer 12

1. Methanol
2. Ethanol
3. Propanol
4. Butanol
5. Pentanol

Question 13

Draw propanol.

Answer 13

Same as propane structure but replace 1 of the hydrogens with OH

Question 14

Describe what happens when ethanol reacts with sodium

Answer 14

Effervescence (produces hydrogen)

Question 15

Describe what happens when ethanol burns in air.

Answer 15

Combusts to produce carbon dioxide and water

Question 16

Describe what happens when ethanol is added to water.

Answer 16

Dissolves to make neutral solution

Question 17

Describe what happens when ethanol reacts with an oxidising agent.

Answer 17

Produces carboxylic acid

Question 18

What are the main uses of alcohols?

Answer 18

• Solvents
• Fuels
• Alcoholic beverages

Question 19

Describe two ways an alcohol can be made.

Answer 19

• Hydration of alkenes using steam
• Fermentation of glucose with yeast (warm, moist, anaerobic conditions)

Question 20

What is the functional group of a carboxylic acid?

Answer 20

-COOH

Question 21

Name the first four carboxylic acids.

Answer 21

• Methanoic acid
• Ethanoic acid
• Propanoic acid
• Butanoic acid
• Pentanoic acid

Question 22

Draw butanoic acid.

Answer 22

• 4 carbon chain (SCB) bonded with hydrogen atoms (SCB)
• Last carbon bonded with oxygen (DCB) and oxygen with hydrogen (SCB)

Question 23

Describe what happens when ethanoic acid reacts with calcium carbonate.

Answer 23

Releases carbon dioxide (could be tested using limewater)

Question 24

Describe what happens when ethanoic acid reacts with ethanol

Answer 24

Produces an ester (ethyl ethanoate)

Question 25

Describe what happens when ethanoic acid is added to water

Answer 25

Weakly acidic solution

Question 26

Explain why carboxylic acids are described as weak acids.

Answer 26

When dissolved in water they incompletely ionise and release hydrogen ions