oxidation of food

Question 1

oxidation

Answer 1

increase in oxygen to hydrogen ratio
- loss of hydrogen from a molecule or gain of oxygen

Question 2

reduction

Answer 2

decrease in oxygen to hydrogen rato

Question 3

aldehydes and ketones

Answer 3

molc containing carbonyl functional group (C=O)

Question 4

antioxidants

Answer 4

molc that prevent unwanted oxidation reactions occurring
- easily oxidised substances

Question 5

2 stages of primary alcohols being oxidised

Answer 5

1. primary alc to aldehyde
2. aldehyde to carboxylic acid

Question 6

1. primary to aldehyde

Answer 6

2 H molc from primary and 1 O molc moved to product forming aldehyde
- decrease in H atoms

Question 7

2. aldehyde to carboxylic acid

Answer 7

2 H from aldehyde and 1 O produce carboxylic acid with COOH
- increase in O atoms

Question 8

aldehyde structure

Answer 8

• end in -al
• functional group CHO
• no need for number infront of -al in systematic name
• hydrogen bonded to carbonyl group unlike ketones

Question 9

ketone structure

Answer 9

compound which contains the carbonyl group at a position within the hydrocarbon chain where all C atoms linked with single bonds
- CO
- contains position number before -one

Question 10

how to distinguish between aldehydes and ketones

Answer 10

using 3 oxidising agents which will oxidise aldehyde but not ketone
- potassium dichromate
- fehling solution
- tollens regent

Question 11

potassium dichromate

Answer 11

orange –> blue

Question 12

fehlings solution

Answer 12

blue –> orange/red

Question 13

tollens reagent

Answer 13

colourless –> silver