Organic chemistry (P2)

Question 1

Explain the formation of crude oil.

Answer 1

Remains of ancient biomass consisting mainly of plankton that was buried in the mud for millions of years

Question 2

What is crude oil?

Answer 2

A mixture of lots of different hydrocarbons

Question 3

What are hydrocarbons?

Answer 3

Molecules made from hydrogen and carbon atoms only

Question 4

True or false: crude oil is finite

Answer 4

True

Question 5

What is the formula for hydrocarbons

Answer 5

Cⁿ + H ²ⁿ+²

Question 6

Explain 3 ways the length of the carbon chain in a hydrocarbon affects it’s property.

Answer 6

.The longer the chain, the more viscous (gloopy) it is
.The shorter the chain, the more volatile (how easily it vaporises) it is
. The shorter the chain, the more flammable it is

Question 7

What are the 4 first alkanes?

Answer 7

Methane
Ethane
Propane
Butane

Question 8

What is the equation for the complete combustion of hydrocarbons?

Answer 8

Hydrocarbon + oxygen -> carbon dioxide + water (+energy)

Question 9

What is oxidised in the complete combustion of hydrocarbons?

Answer 9

Hydrogen and carbon

Question 10

Is fractional distillation a chemical or a physical process?

Answer 10

Physical process

Question 11

Explain the process of fractional distillation.

Answer 11

1) Crude oil is heated to vaporise and enters fractionating column
2) Temperature gradient in column (hotter at the bottom, cooler at the top)
3) Long hydrocarbons have higher boiling points so condense near the bottom
4) Shorter hydrocarbons have lower boiling points so condense near the top
This separates crude oil mixture into different fractions

Question 12

What is a fraction?

Answer 12

A group of hydrocarbons that have similar carbon chain lengths so have similar boiling points.

Question 13

What are the fractions separated from fractional distillation used for?

Answer 13

Shorter chain hydrocarbons used for fuels.

Longer chain hydrocarbons used for feedstock to make solvents, lubricants.

Question 14

What is cracking? Why’s it done?

Answer 14

Longer hydrocarbons are broken down to produce smaller, more useful molecules. They are more useful because they are flammable so make good fuels.

Question 15

What are the products of cracking?

Answer 15

Alkanes and alkenes

Question 16

Is cracking a chemical or physical process?

Answer 16

Chemical process

Question 17

What type of reaction is cracking?

Answer 17

Thermal decomposition

Question 18

What are the 2 methods of cracking and what are the conditions needed for each?

Answer 18

Catalytic cracking:
.High temperature
.Catalyst

Steam cracking:
.High temperature
.Steam

Question 19

Are alkanes or alkenes unsaturated? What does unsaturated mean?

Answer 19

Alkenes
As they have a double carbon-carbon bond

Question 20

What is the formula for alkenes?

Answer 20

Cⁿ+H²ⁿ

Question 21

Are alkanes or alkenes more reactive?

Answer 21

Alkenes

Question 22

What are the first four alkenes?

Answer 22

Ethene (2 Cs)
Propene (3Cs)
Butene (4Cs)
Pentene (5Cs)

Question 23

What are the results of the bromine test?

Answer 23

Alkanes make the solution stay orange.
Alkenes make the solution become colourless.

Question 24

True or false: alkenes undergo complete combustion

Answer 24

False, they undergo incomplete combustion.

Question 25

What can you see when alkenes are burned?

Answer 25

Smoky yellow flame

Question 26

True or false: all you have to do in the bromine test is add the alkene to bromine water.

Answer 26

False you have to shake it.

Question 27

What do all alcohols have?

Answer 27

The functional group -OH

Question 28

Name 3 uses of alcohols.

Answer 28

.Fuels .Solvents .Alcoholic drinks

Question 29

Name the first 4 alcohols.

Answer 29

.Methanol .Ethanol .Propanol .Butanol

Question 30

What is the formula for alcohols?

Answer 30

Cⁿ+H (²ⁿ+1)+OH

Question 31

Except for combustion, name 2 things alcohols can react with and state the products.

Answer 31

Can react with SODIUM to produce HDYROGEN. Can be OXIDISED to produce a CARBOXYLIC ACID.

Question 32

Why are some alcohols used as solvents?

Answer 32

They can dissolve lots of things including some things that water can't dissolve.

Question 33

Why are some alcohols used as fuels?

Answer 33

Burn fairly cleanly and not smelly.

Question 34

What's the reaction for fermentation?

Answer 34

Sugar -> ethanol + carbon dioxide

Question 35

What enzyme is used in fermentation?

Answer 35

Yeast

Question 36

What are the ideal conditions for fermentation?

Answer 36

.37 degrees Celsius .In a slightly acidic solution .Under anaerobic conditions

Question 37

What do all carboxylic acids have?

Answer 37

A functional group of -COOH

Question 38

What are the first four carboxylic acids?

Answer 38

.Methanoic acid .Ethanoic acid .Propanoic acid .Butanoic acid

Question 39

What is the equation for the reaction of a carboxylic acid and a carbonate.

Answer 39

carboxylic acid + carbonate -> salt + water + carbon dioxide

Question 40

What happens when carboxylic acids dissolve in water?

Answer 40

Partially ionise to form weak acid solutions

Question 41

What would the name of the salt be when ethanoic acid reacts with sodium carbonate?

Answer 41

Sodium ethanoate

Question 42

What is the equation for when carboxylic acids react with alcohols?

Answer 42

Carboxylic acid + alcohol -> ester + water

Question 43

What catalysts are used in the reaction of carboxylic acids and alcohols?

Answer 43

Acid catalysts

Question 44

What do all esters have?

Answer 44

A functional group of -COO-

Question 45

What is a polymer?

Answer 45

A large molecule made by the joining of small molecules (monomers)

Question 46

Give 2 conditions needed for polymerisation.

Answer 46

.High temperature .Catalyst