Alcohols (Cambridge (CIE) O Level Chemistry): Exam Questions

A student found a recipe for making elderberry wine by fermentation.

• 1kg elderberries

• 0.5kg sugar

• 10g yeast granules

• 3dm³ water

The student decided to make some elderberry wine using the apparatus below.

The student carried out the following method.

Step 1 The elderberries were crushed.

Step 2 The crushed elderberries and sugar were added to the water and the mixture was boiled for ten minutes. The crushed elderberries were then separated from the mixture.

Step 3 Yeast was added to the liquid when it had cooled to room temperature.

Suggest the purpose of the airlock in the apparatus.

What apparatus could be used in Step 1?

Draw a labelled diagram of the apparatus used to separate the crushed elderberries from the mixture in Step 2.

Why was the yeast in Step 3 not added until the liquid was at room temperature?

i)

State one observation during the fermentation.

[1]

ii)

Suggest how the rate of the fermentation reaction could be measured.

[2]

Name the method that could be used to separate ethanol from the fermented mixture.