Unit 2: Natures Chemistry

Question 1

What do you call a compound containing only carbon to carbon single bonds?

Answer 1

Saturated

Question 2

What happens in an addition reaction? Simple

Answer 2

Two molecules combine to form one

Question 3

Name 3 properties of isomers (structure, series, properties)

Answer 3

Isomers:
- are compounds with the same molecular formula but different structural formulae
- may belong to different homologous series
- usually have different physical properties

Question 4

What is volatility?

Answer 4

Ease of evaporation

Question 5

What are 4 ways that you can predict the solubility, boiling point and volatility of a compound?

Answer 5

1 - the presence of O-H or N-H bonds, which implies hydrogen bonding
2 - the spatial arrangement of polar covalent bonds which could result in a molecule possessing a permanent dipole
3 - molecular size which would affect LDFs
4 - the polarities of solute and solvent. Polar or ionic compounds tend to be soluble in polar solvents, non polar compounds tend to be soluble in non-polar solvents

Question 6

How else can you explain solubility, boiling point and volatility!

Answer 6

Type and strength of intermolecular forces present

Question 7

What is an alcohol?

Answer 7

A molecule containing a hydroxyl functional group, -OH group

Question 8

What three ways can alcohols be classified?

Answer 8

Primary, secondary and tertiary

Question 9

What do you call an alcohol containing 2/3 hydroxyl groups?

Answer 9

2 - diols
3 - triols

Question 10

What do hydroxyl groups do? (Polarity/bonding)

Answer 10

Make alcohols polar, this gives rise to hydrogen bonding

Question 11

What is a carboxylic acid?

Answer 11

A molecule containing the carboxylic functional group, -COOH

Question 12

Carboxylic acids can react with bases:

A metal oxide + a carboxylic acid = ?

Answer 12

A salt + water

Question 13

Carboxylic acids can react with bases:

A metal hydroxide + a carboxylic acid = ?

Answer 13

A salt and water

Question 14

Carboxylic acids can react with bases:

A metal carbonate + a carboxylic acid = ?

Answer 14

A salt + water + carbon dioxide

Question 15

What is an ester?

Answer 15

A molecule containing an ester link, -COO-

Question 16

Esters can be named given the: 2 reasons

Answer 16

1 - the name of their parent alcohol and carboxylic acid
2 - structural formulae of esters formed from primary, straight chain alcohols containing no more than eight carbons and straight-chain carboxylic acids containing no more than eight carbons

Question 17

What are esters used for?

Answer 17

Flavourings, fragrances (pleasant fruity smell), solvents for non polar compounds that don’t dissolve in water

Question 18

Molecular formulae can be befitted and structural formulae drawn for esters given the: (2 things)

Answer 18

1 - systematic names of esters formed from primary, straight-chain alcohols containing no more than eight carbons and straight-chain carboxylic acids containing no more then eight carbons
2 - structural formulae of their patent alcohol and carboxylic acid

Question 19

How are esters formed?

Answer 19

A condensation reaction between an alcohol and a carboxylic acid

Question 20

What happens in a condensation reaction?

Answer 20

Two molecules are joined together with the elimination of a small molecule

Question 21

What happens when an ester link is formed?

Answer 21

By the reaction between a hydroxyl group and a carboxyl group, the small molecule eliminated is water

Question 22

What happens when esters are hydrolysed?

Answer 22

It produces an alcohol and a carboxylic acid

Question 23

What happens in a hydrolysis reaction?

Answer 23

A molecule reacts with water to break down into smaller molecules

Question 24

The products of the hydrolysis of an ester can be named given the: (2 things)

Answer 24

1 - name of the ester
2 - structural formula of an ester formed from a straight-chain or branched alcohol and a straight-chain or branched carboxylic acid, each containing no more than eight carbons in their longest chain

Question 25

How are edible fats and edible oils formed?

Answer 25

From the condensation of glycerol and three carboxylic acid molecules

Question 26

What are carboxylic acids known as?

Answer 26

Fatty acids

Question 27

Which has a higher melting point? Edible oils or edible fats

Answer 27

Edible fats

Question 28

What do double bonds in fatty acid chains do?

Answer 28

Prevent oil molecules from packing closely together, so the greater the number of double bonds present, the weaker the van der waals forces of attraction. The greater the degree of unsaturation, the lowers the melting point

Question 29

What does having a greater degree of unsaturation mean?(bp)

Answer 29

The lower the boiling point

Question 30

What are fats and oils? 2 things

Answer 30

1 - a concentrated source of energy
2 - essential for the transport and storage of fat-soluble vitamins in the body

Question 31

What are soaps produced by?

Answer 31

The alkaline hydrolysis of edible fats and edible oils

Question 32

What does hydrolysis produce?

Answer 32

Three fatty acid molecules and one glycerol molecule

Question 33

What neutralises fatty acid molecules? What does it form?

Answer 33

The fatty acid molecules are neutralised by the alkali, forming water-soluble, ionic salts called soaps

Question 34

What can soap be used to remove?

Answer 34

Non-polar substances such as oil and grease