C7 Hydrocarbons

Question 1

Crude oil

Answer 1

A fossil fuel

A finite resource

Question 2

Hydrocarbons

Answer 2

Molecules made from carbon and hydrogen only

Smallest hydrocarbon is methane

Question 3

Homologous series

Answer 3

All alkanes have the same general formula C2H2n+2

Question 4

Fractional distillation

Answer 4

The mixture of oils in crude oil separated into fractions

Question 5

Products from crude oil

Answer 5

Fuel- liquified petroleum gas(LPG), petrol,kerosene, diesel oil, heavy fuel oil
Petrochemicals- solvents, lubricants, polymers, detergents

Question 6

Separating fractions

Answer 6

A fractional distillation column is used where the top is the coolest
Each oil is separated out at different points as the gases with low boiling points go to the top and heavier gas stay at the bottom

Question 7

Why can be fractions be separated?

Answer 7

As molecules with larger chains have stronger bonds so have a higher boiling point than molecules in shorter weaker chains

Question 8

Using fuels

Answer 8

Petrol and diesel in car engines
LPG in camping stoves
Kerosene in aircrafts
Heavy fuel oil in ships

Question 9

What happens to the boiling point when molecules get larger

Answer 9

The boiling point increases

Question 10

Larger molecules means

Answer 10

Boiling point and viscosity increases

Flammability decreases

Question 11

What happens if you burn a hydrocarbon

Answer 11

Water and carbon dioxide are produced

Question 12

Incomplete combustion

Answer 12

When a fuel burns in a shortage of oxygen

Products are water, carbon monoxide and carbon

Question 13

Complete combustion

Answer 13

CH4 + 2O2 = CO2 + 2H2O

Carbon and hydrogen in fuels are oxidised

Question 14

Supply and demand

Answer 14

The solution to the demand for petrol is cracking.

Question 15

Cracking

Answer 15

Kerosene can be cracked into petrol
Essentially it is using a night temperature and a catalyst to break long molecules into smaller molecules that are in a greater demand. The alkenes produced can also help in the production of many other chemicals

Question 16

Testing for products of cracking

Answer 16

Bromine water is used to test for alkenes. When solution turns from orange to colourless you know there is an alkene
An alkane however will keep the solution orange as they don’t react

Question 17

Alkanes and alkenes

Answer 17

Alkanes are far less reactive than alkenes

Question 18

Alkenes

Answer 18

Another series of hydrocarbons 
They have a double carbon bond 
Unsaturated molecules as they contain two fewer hydrogen atoms than the alkane 
Have the formula CnH2n
Generally produce incomplete combustion

Question 19

Functional groups

Answer 19

Usually attached to the carbon skeleton

For an alkene the double bond breaks and the addition of atoms can be added to either side of the double bond

Question 20

The alcohol series

Answer 20

Contains functional group OH
Names of alcohols end in ol
Aqueous solutions of ethanol are produced when sugar solutions are fermented using yeast

Question 21

Methanol, ethanol, propanol and butanol

Answer 21

Are used as fuels and solvents
Dissolve in water to form an neutral solution
React with sodium to produce hydrogen
Burn in air to produce carbon dioxide and water
Can be oxidised to produce carboxylic acids

Question 22

Making alcohol

Answer 22

Fermentation needs:
Water
Enzymes from yeast
Temp between 25-40 degrees Celsius 
Absence of oxygen

Question 23

Carboxylic acids

Answer 23

Contain carbon oxygen and hydrogen but still behave as acids
They dissolve in water to produce acidic solutions
React with carbonates to produce carbon dioxide
Have functional group of COOH
Weak acids so are particularly ionised in water

Question 24

Polymer

Answer 24

A very big molecule
A very long chain molecule
Molecule made from many small molecules called monomers

Question 25

Polymerisation

Answer 25

Reaction When many monomers are joined together to make a polymer Small monomers join together to make polymers

Question 26

2 ways polymers can be made:

Answer 26

Addition | Condensation

Question 27

Addition polymers

Answer 27

Uses alkenes that have a double bond and addition can occur across this bond High pressure and a catalyst

Question 28

Condensation reactions

Answer 28

Need at least 2 monomers of different functional groups joined together to create a new functional group When they react they join together and lose small molecules such as water Single reaction can be used multiple times to form long chains of molecules

Question 29

Amino acids functional groups

Answer 29

H2N-R-COOH

Question 30

Polypeptides

Answer 30

Amino acids react by condensation polymerisation to form these bonds Different amino acids combined make different polypeptides

Question 31

3 carbohydrates

Answer 31

Starch Sugar Cellulose

Question 32

Carbohydrates

Answer 32

biological compounds made from carbon, hydrogen and oxygen

Question 33

Monosaccharides

Answer 33

Simple sugars | Glucose and fructose

Question 34

Polysaccharides

Answer 34

Very long natural polymers Starch Cellulose

Question 35

DNA

Answer 35

2 polymer chains made from monomers called nucleotides joined in the shape of a double helix

Question 36

Nucleotide

Answer 36

Made from sugar molecule, a phosphate group and a base | 4 different bases so 4 different nucleotides

Question 37

Proteins

Answer 37

Natural polymers made from amino acids | Proteins differ from one another as there are 20 different amino acids arranged in different sequences