8) SOAPS AND EMULSIONS

Question 1

What reactions occur in the making of soaps

Answer 1

Hydrolysis and neutralisation

Question 2

What are fats and oils

Answer 2

Esters

Question 3

Describe the process of making a soap

Answer 3

1) fat is hydrolysed to form glycerol and 3 fatty acids
2) the fatty acid is then neutralised by an alkali and water is produced. The salt formed is soap
3) OH comes from alkali, H comes from fatty acid (Carboxyl group)

Question 4

Name the two types of alkalis used in the process of making a soap

Answer 4

Sodium hydroxide

Potassium hydroxide

Question 5

How do soaps work

Answer 5

• soaps have a polar head and a non polar tail
• the polar head can dissolve in water and the non polar tail can dissolve in grease
• The soap surrounds the grease and the polar head hydrogen bonds to water so dissolves, keeping the droplet of grease in suspension

Question 6

What are emulsions and name an emulsion you would find in real life

Answer 6

An emulsion is a mixture of two or
More immiscible liquid (water & oil), where the droplet of one liquid is held in suspension in another liquid by an emulsifier

Real life:
Mayonnaise
Milk

Question 7

Why are emulsifiers used

Answer 7

Used to hold two immiscible liquids together

Question 8

Why are emulsifiers used in industry

Answer 8

• help food look appealing

* help to maintain quality of food

Question 9

How are emulsifiers made

Answer 9

Reacting fatty acids with glycerol

Mono-glycerides:
Reacting 1 fatty acid with glycerol

Di-glyceride:
Reacting two fatty acids with glycerol

Question 10

How do emulsifiers work

Answer 10

• emulsifier have a polar head and a non polar tail
• the polar head can dissolve in water-soluable compound and the non polar tail can dissolve in the oil soluable compound
• it surrounds the droplet keeping it in suspension