Glycerides & their Uses

Question 1

How to identify an ester

Answer 1

Ester carboxylate group (COO)

Name contain “yl-oate” ending

Question 2

How are esters formed

Answer 2

Condensation reaction between a carboxylic acid and an alcohol (esterification)

Question 3

What happens in a condensation reaction

Answer 3

two molecules join together with the elimination of a small molecule, in this case, water

Question 4

General formula for esterification

Answer 4

Alcohol + Carboxylic Acid ⇌ Ester + Water

Question 5

Characteristics of esters

Answer 5

Esters have characteristic smells and are used as fragrances and flavourings

Question 6

Uses of esters

Answer 6

Industrial solvents
Flavourings & perfumes
Medicines
Making soaps

Question 7

What is the ester link formed by

Answer 7

The reaction of a hydroxyl group and the carboxyl group

Question 8

What happens when you hydrolyse an ester

Answer 8

The parent carboxylic acid and parent alcohol are obtained

Question 9

What happens in a hydrolysis reaction

Answer 9

A molecule reacts with water, breaking down into smaller molecules

Question 10

What are edible fats and oils

Answer 10

Esters formed from the condensation of glycerol and three carboxylic acid molecules

Question 11

What is glycerol

Answer 11

Propane-1,2,3-triol

Question 12

Which has lower BP: oils or fats?

Answer 12

Edible oils have lower melting points than edible fats

Question 13

How do unsaturated compounds react with bromine solution

Answer 13

Unsaturated compounds quickly decolourise bromine solution

Question 14

Why do oils have lower BPs than fats?

Answer 14

Double bonds prevent oils from packing together as they cause kinks in the chain i.e. weaker van der waals forces that are easy to overcome
Higher the degree of unsaturation = lower melting point