KA1- Esters, Fats And Oils

Question 1

Esters

Answer 1

Formed by reacting an alcohol with a Carboxylic acid - condensation reaction because water is formed
Pleasant, fruity smell

Question 2

Naming esters

Answer 2

First part ends in yl from the alcohol
Second part end in oate from the acid
Eg methanol+ethanoic acid—) methy ethanoate

Question 3

Methyl ethanoate full structural

Answer 3

H O H
| || |
H—C—C—O—C—H
| |
H H

Question 4

Uses of esters

Answer 4

In scented products (deodorants, perfumes)
Nail varnish
Spray paints
Flavourings
Solvents for non to polar compounds that do not dissolve in water

Question 5

Properties of esters

Answer 5

Abe to dissolve a wide variety of compounds
Relatively low boiling points allowing them to evaporate easily

Question 6

Hydrolysis of esters

Answer 6

When an ester reacts with water, the ester breaks down to from an alcohol and carboxylic acid

Question 7

Fats and oils

Answer 7

Esters formed from the reaction of glycerol (an alcohol) and three fatty acid molecules
Non polar structure allows them to dissolve a number of essential vitamins

Question 8

Glycerol

Answer 8

Alcohol with three -OH groups so can form 3 ester links with the fatty acid molecules
The product ester formed is a fat or oil and can be called a triglyceride because of the 3 ester links
Structure of the fatty acids which join glycerol affects whether the triglyceride formed is a fat or an oi

Question 9

Room temperature

Answer 9

Fats are solids
Oils are liquids

Question 10

Fats

Answer 10

Formed from saturated fatty acids
Solid
High degree of saturation gives the fat molecules an even, regular structure which allows them to pack closely together- efficient packing increases teh number of van der Waals’ attraction making the attraction between fat molecules greater than the attraction between oil molecules
When heated, van der Waals’ attractions are broken and teh fat melts

Question 11

Oils

Answer 11

Formed from unsaturated fatty acids
Liquid
Double bonds cause the molecules to have an uneven distorted structure making it difficult for them to pack closely together, resulting in fewer can der Waals’ tractions between oil molecules, therefore takes less energy to break apart the oil molecules which means that oils have a lower melting point than fats

Question 12

Glycerol properties

Answer 12

Very viscous and high boiling point (due to 3 -OH groups)
Allows glycerol molecules to form more hydrogen bonds between molecules than alcohol Ds with only a singel -OH group

Question 13

Fatty acids

Answer 13

Carboxylic acids that contain a large number of carbon atoms