Unit 2 - Nature's Chemistry (Oxidation of Food)

Question 1

What happens when foods are exposed to oxygen in the air?

Answer 1

Their chemical composition changes and they begin to break down. Foods will lose their nutritional value as they begin to discolour and break down. The food will oxidise with the air and spoil as a result.

Question 2

What are antioxidants?

Answer 2

Molecules that slow the rate of oxidation in foods. They play an important role in preventing our food from spoiling too quickly by stopping oxidation reactions from taking place. The antioxidant molecules are reducing agents, they cause other substances to be reduced while being oxidised themselves. Some examples of antioxidants include vitamin C and vitamin E.

Question 3

What can be used to partially oxidise alcohols?

Answer 3

Oxidising agents

Question 4

What are primary alcohols oxidised into?

Answer 4

Aldehydes then carboxylic acids

Question 5

What are secondary alcohols oxidised into?

Answer 5

Ketones

Question 6

Can tertiary alcohols be oxidised?

Answer 6

No

Question 7

What are carboxylic acids reduced into?

Answer 7

Aldehydes then primary alcohols

Question 8

What are ketones reduced into?

Answer 8

Secondary alcohols

Question 9

What is oxidation?

Answer 9

The loss of electrons and an increase in the oxygen to hydrogen ratio (loss of hydrogen or gain of oxygen).

Question 10

What is reduction?

Answer 10

The gain of electrons and a decrease in the oxygen to hydrogen ratio (gain of hydrogen or loss of oxygen).