Hertswood Academy Gcse Chemistry C1 6 Plant Oils And Their Uses

Front 1

1. How can oils be extracted?

Back 1

• Crushed and pressed• Distilled

Front 2

2. Why are oils important as foods and fuels?

Back 2

• Contain a lot of energy

• Provide us with vitamins

Front 3

3. What are the advantages of cooking with oil?

Back 3

• Oils have higher boiling point so food cooks more quickly

• Different textures and flavours

Front 4

4. What are the (possible) disadvantages of cooking with oil?

Back 4

• May contain more energy than is needed

Front 5

5. What do unsaturated hydrocarbons contain?

Back 5

• At least one carbon = carbon double bond

Front 6

6. How can they be detected/tested?

Back 6

• By reacting with Bromine water

Front 7

7. What will be the result of the oil is unsaturated?

Back 7

• The bromine water will decolourise (turn from orange to colourless)

Front 8

8. What will be the result if the oil is saturated?

Back 8

• The bromine water will remain orange (no change)

Front 9

9. Why are unsaturated oils hardened?

Back 9

• So they have a higher melting point

• Become more solid at room temperature and can be used as spreads

Front 10

10. How are oils hardened?

Back 10

• Reacted with hydrogen gas – H2

• In presence of Nickel catalyst

• 60⁰C

Front 11

11. What happens during this reaction?

Back 11

• Hydrogen adds across the carbon = carbon double bond

Front 12

12. Do oil and water mix?

Back 12

• No they are said to be immiscible

Front 13

13. What happens when oil and water are shaken together?

Back 13

• Tiny droplets of one liquid spread through the other liquid

• This is called an emulsion

Front 14

14. How are emulsions useful?

Back 14

• Thicker than oil and water

• Better texture

• Better coating ability

• Appearance

Front 15

15. What happens if an un-stabilised emulsion is left to stand?

Back 15

• The two liquids separate (split into two layers)

Front 16

16. How can an emulsion be made more stable?

Back 16

• By adding an emulsifier that stops them separating

Front 17

17. How do emulsifiers work?

Back 17

• One end is hydrophobic (water hating) and sits in the oil

• One end is hydrophilic (water loving) and sits in the water

Front 18

18. What does a diagram of an emulsion look like?

Back 18

Front 19

19. Give some examples of oil in water emulsions

Back 19

• Milk

• Ice cream

Front 20

20. Give some examples of water in oil emulsions

Back 20

• Butter

• Skin cream