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Question 1

What happens when proteins are heated

Answer 1

.when proteins are heated the intermolecular forces within the protein are broken. There is a change in the shape of the protein. The protein becomes denatured - this is irreversible cooking changes the texture of foods

Question 2

Name the three types of alcohols

Answer 2

.primary secondary tertiary

Question 3

Definition of oxidation when applied to _____ compounds

Answer 3

.invrease in oil and hydrogen ratio

Question 4

Which of the three types of alcohols can be oxidised

Answer 4

.primary and secondary

Question 5

Type of compound formed when a primary alcohol is oxidised is …

Answer 5

.carboxylic acid and aldehyde

Question 6

Type of compound formed when secondary alcohol is oxidised ?

Answer 6

.ketone

Question 7

What are aldehydes

Answer 7

.aldehydes are formed by the oxidation of primary alcohol. Aldehydes have the car only group . On the end of the molecule.
They end in “al”

Question 8

What are ketones

Answer 8

.ketones formed by oxidation of a secondary alcohol. Have carbonyl functional group and end in one. Functional in middle

Question 9

How can aldehydes and ketones be further oxidised

Answer 9

.aldehydes can be further oxidised to form carboxylic acids though secondary can’t wait to

Question 10

Examples of oxidising agents

Answer 10

.potassium dichromate
Fehilings
Tollens

Question 11

How can you distinguish between an aldehyde and a ketone

Answer 11

.plave substance in test tube with oxidising agent. Heat in water bath and see the colour change. ( aldehyde if colour change and no colour change is a ketone)

Question 12

Why does an apple go brown when exposed to air and no skin

Answer 12

.substancws in the air are reacting oxygen causing it to go brown

Question 13

Examples of manufacturing process used to prevent food being exposed to oxygen

Answer 13

.vaccuum packed ready meals to prevent oxidation

Question 14

What are antioxidants

Answer 14

.they are good reducing agents which means they will get oxidised in preference to the food. Example of naturally occurring reducing agents are vitamin E and C

Question 15

What is volatility

Answer 15

.volatility is a measure of how easily a substance vaporises. A volatile substance vaporises easily

Question 16

What do the volatile molecules contained naturally in the food do

Answer 16

.volatile molecules contain naturally in food the food flavour

Question 17

Why do some foods taste better when cooked in oil/water

Answer 17

.if the food molecule is non polar then it should be cooked in water
If polar should be cooked in oil

This is to prevent flavour loss

Question 18

How does molecule size effect volatility and boiling point

Answer 18

.the larger the molecule the higher the boiling point due to stronger/ increased van der waals forces

The larger the molecule the less volatile is (due to increased van der waals forces

Question 19

How does the functional group prevent a flavour molecule affect boiling point, solubility and volatility

Answer 19

.

Question 20

Where is the best reducing agent in ECS

Answer 20

Top right best reducing bottom left best oxidising

Must be higher on the right than the left for reaction to occur

Question 21

Why might no indicator need to be used?

Answer 21

It is self indicating

Question 22

Definition for enthalpy or combustion

Answer 22

The enthalpy change when one mole of a substance is completely burned in oxygen

Question 23

Definition for enthalpy of neutralisation

Answer 23

The enthalpy change when an acid is neutralised to form one mole of water