Fats and Oils

Question 1

main use of fats and oils

Answer 1

1. concentrated source of energy
2. are essential for the transport and storage of fat-soluble vitamins in the body. non-polar structure allows them to dissolve essential vitamins such as A and D.

Question 2

other uses of fats and oils

Answer 2

• edible oils used as fuels such as bio-diesel (more important as fuels from crude oil become scarcer/more expensive)
• lubricants for some agricultural machinery made from veg oil to prevent risk of harmful mineral oils contaminating future food stuffs.

Question 3

structure of fats/oils

Answer 3

• 1x glycerol backbone (alcohol)
• 3x fatty acids (carboxylic acids)
• 3x ester linkages

Question 4

what is glycerol also known as?

Answer 4

propan-1,2,3-triol

Question 5

what homologous series do fats and oils belong to?

Answer 5

esters

Question 6

in what reaction are fats and oils made?

Answer 6

esterification/condensation reaction

Question 7

what can a fat or oil also be referred to as?

Answer 7

triglyceride

Question 8

state of fats and oils at room temp

Answer 8

fats are solid

oils are liquids

Question 9

what determines if the triglyceride is a fat or oil?

Answer 9

the structure of the fatty acid chain

Question 10

where do fats tend to come from?

Answer 10

animals

Question 11

where do oils tend to come from?

Answer 11

fish and plants

Question 12

are fats and oils unsaturated or saturated?

Answer 12

fats are saturated

oils are saturated

Question 13

do fats or oils have a higher mp

Answer 13

fats have higher mp

oils have lower mp

Question 14

in other words, what is degree of unsaturation?

Answer 14

how many c=c are present

Question 15

monounsaturated

Answer 15

one c=c

Question 16

polyunsaturated

Answer 16

more than 1 c=c

Question 17

testing degree of unsaturation

Answer 17

more unsaturated the fatty acid, the more bromine it can react with. (more C=C for Br-Br to add on to)
end point of titration colourless–>yellow when no more Br2 can add on as the fatty acid has become fully saturated.

Question 18

iodine number

Answer 18

mass of iodine in grams that will react with 100g of oil

Question 19

using iodine to test degree of unsaturation

Answer 19

the iodine reacts with the c=c bonds, so the greater the iodine number, the greater the number of double bonds.

Question 20

determining degree of unsaturation using formula

Answer 20

it is saturated if it fits the general formula CnH2n+1
if it is not saturated there is 1 double bond for each pair of hydrogen’s lost.
x2+1

Question 21

process used to convert oils into fats

Answer 21

hydrogenation

Question 22

what happens to an oil when it is ‘hardened’?

Answer 22

hydrogen is added on to the c=c in the oil which reduces the degree of unsaturation which increases the melting point.

Question 23

what catalyst is used in hardening of oils

Answer 23

nickel Ni catalyst

Question 24

example of hardening of oils in real life

Answer 24

production of margarine

Question 25

edible fats and oils are esters formed from the…

Answer 25

condensation reaction of glycerol with three fatty acid molecules

Question 26

how many ester links can glycerol form with fatty acid molecules?

Answer 26

3

Question 27

the greater the number of drops (longer titration)…

Answer 27

more unsaturated the oil.

Question 28

end point of titration of fats/oils against bromine

Answer 28

when all double bonds have been used up

trace of bromine remains (no further decolouration)