Alcohols

Question 1

What is the general formula of an alcohol?

Answer 1

CnH2n+1OH.

Question 2

What is an alcohol with 2 carbons formula?

Answer 2

C2H5OH.

Question 3

What do all alcohols contain?

Answer 3

The same -OH functional group.

Question 4

What is a homologous series?

Answer 4

A group of chemicals that react in a similar way because they have the same functional group - Alcohols.

Question 5

What are the first three alcohols in the homologous series?

Answer 5

• Methanol.
• Ethanol.
• Propanol.

Question 6

What is the formula and diagram for methanol?

Answer 6

CH3OH.
     H
      |
H--C--O--H
      |
     H

Question 7

What is the formula and diagram for ethanol?

Answer 7

C2H5OH.
     H  H
      |    |
H--C--C--O--H
      |    |
     H  H

Question 8

What is the formula and diagram for propanol?

Answer 8

C3H7OH.
     H  H  H
      |    |    | 
H--C--C--C--O--H
      |    |    | 
     H  H  H

Question 9

What do the first three alcohols have?

Answer 9

Similar properties.

Question 10

What are alcohols?

Answer 10

Flammable.

Question 11

What do alcohols produce when they burn in air?

Answer 11

• Carbon dioxide.

- Water.

Question 12

What are the properties of the first three alcohols?

Answer 12

• They all dissolve completely in water to form neutral solutions.
• They all react with sodium to give hydrogen and alkoxides.

Question 13

What is the main alcohol in alcoholic drinks?

Answer 13

Ethanol.

Question 14

Why is ethanol used in alcoholic drinks over the other alcohols?

Answer 14

As it is not as toxic as methanol (which causes blindness if drunk), but it still damages the brain and liver.

Question 15

What are alcohols used as?

Answer 15

• Solvents.

- Fuels.

Question 16

Why are alcohols used as solvents?

Answer 16

They can dissolve most compounds that water can dissolve, and they can also dissolve substances that water can’t dissolve (e.g. hydrocarbons, oils and fats).

Question 17

What is ethanol the solvent in?

Answer 17

• Perfumes.

- Aftershave lotions.

Question 18

What does ethanol with chemicals added make?

Answer 18

Methylated spirit (meths)

Question 19

Why is ethanol the solvent in perfumes and aftershave lotions?

Answer 19

As it can mix with both the oils and the water.

Question 20

What are the uses of methylated spirit?

Answer 20

• Clean paint brushes.

- Fuel.

Question 21

What is methylated spirit to humans?

Answer 21

Poisonous to drink.

Question 22

How do we avoid drinking the poisonous methylated spirit by mistake?

Answer 22

A purply-blue dye is added.

Question 23

What is ethanol used as?

Answer 23

A fuel in spirit burners.

Question 24

Why is ethanol used as a fuel in spirit burners?

Answer 24

It burns fairly cleanly, without a smell.

Question 25

What else can we do with ethanol?

Answer 25

Mix it with petrol and use it as a fuel for cars.

Question 26

Why do we mix ethanol with petrol to use it as a fuel in cars?

Answer 26

Since pure ethanol is clean burning, the more ethanol in a petrol/ethanol mix, the less pollution produced.

Question 27

How do some countries that don’t have oil deposits produce ethanol?

Answer 27

If they have plenty of land and sunshine, they can grow lots of sugarcane to ferment to form ethanol.

Question 28

What is an advantage of fermentation to produce ethanol?

Answer 28

Sugar cane is a renewable source.

Question 29

What does ethanol give when it reacts with sodium?

Answer 29

• Sodium ethoxide (2C2H5ONa)

- Hydrogen (H2).