Organic Chemistry

Question 1

Define: Hydrocarbon

Answer 1

Compounds that only contain Hydrogen and Carbon atoms only

Question 2

Define: Saturated

Answer 2

Contain maximum number of hydrogen for given number of carbon

Question 3

Define: Unsaturated

Answer 3

The presence of the double bond mean they don’t have as many hydrogen

Question 4

Formula for Alkane

Answer 4

Cn H2n+2

Question 5

Formula for Alkene

Answer 5

Cn H2n

Question 6

Homologous series

Answer 6

Similar structural and Chemical properties, due to similar bonding
General Formula

Question 7

Alkane/Alkene physical trends

Answer 7

1,2,3,4 - Carbon - Gasses

5,6,7,8 - Carbon - Liquids

Question 8

Alkane Combustion

Answer 8

Burn in oxygen

Enough they will give carbon dioxide and water

Question 9

Incomplete combustion

Answer 9

Not enough oxygen

Carbon monoxide/carbon (soot) produced instead of CO2

Question 10

Why is CO poisonous?

Answer 10

Combines with haemoglobin instead of oxygen

Question 11

Substitution reaction

Answer 11

Alkane is substituted by a different atom, like in the reaction with bromine

Question 12

Test for C=C

Answer 12

Shake organic compound with bromine water and the orange water is decolourised. Same for gas, but bubble through the water

Question 13

Alcohols

Answer 13

Contain a -OH group onto the carbon chain

Question 14

Ethanol by Fermentation

Answer 14

Yeast is added to starch and left in warm (30-40*C)
Absence of air.
Enzymes convert sugar into ethanol and CO2

Question 15

Ethanol by hydration of Ethene

Answer 15

Ethene is passed over steam with Phosphoric acid Catalyst

300*C, 60-70 atm. Unreacted material is recycled

Question 16

Dehydration of ethanol to produce ethene

Answer 16

Ethanol is passed over hot aluminium catalyst

Question 17

Pros/Cons of Hydration of Ethene

Answer 17

Pros - Fast and continuous process, Makes pure ethanol

Cons - High amounts of energy, Non-Renewable

Question 18

Pros/Cons of Fermentation

Answer 18

Pros - Renewable, Doesn’t require much energy

Cons - Batch process is slow, Impure ethanol

Question 19

Crude Oil

Answer 19

Finite, Mixture of hydrocarbons

Question 20

Properties of Hydrocarbons

Answer 20

As chains increase: Boiling points increase
Liquids become less volatile
Liquids flow less easily
Bigger hydrocarbons burn less easily

Question 21

Separating Crude oil

Answer 21

Oil is passed into a fractionating column, cooler at top than bottom. Boils, quickly then condenses at certain point to be tapped off

Question 22

Crude oil column at top/at bottom

Answer 22

Top going down less volatile e.g refinery gasses most

Bottom going up less viscous e.g fuel oil

Question 23

The 6 fractions

Answer 23

Bitumen, Fuel Oil
Diesel Oil, Kerosine
Gasoline, Refinery Gasses

Question 24

Uses for Refinery gasses, Gasoline, Kerosine

Answer 24

Refinery Gasses - Domestic heating/cooking
Gasoline - Petrol
Kerosine - Aircraft fuel

Question 25

Uses for Diesel oil, Fuel oil, Bitumen

Answer 25

Diesel oil - Busses, Lorries, some cars Fuel oil - Ships boilers/industrial heating Bitumen - Road making

Question 26

Problems with fractions

Answer 26

Amounts depend on hydrocarbons | Unreactive make into reactive

Question 27

Cracking

Answer 27

Large hydrocarbons are converted into smaller ones, that have more demand

Question 28

How Cracking works

Answer 28

Fraction heated to give gas, then passed over silicon dioxide and aluminium oxide catalyst at 600-700*C. A mixture of single and double bonds could form.

Question 29

Addition polymerisation

Answer 29

Double bond is broken and electrons are used to join neighbouring molecules

Question 30

Polymerisation

Answer 30

The joining up of monomers to make polymers

Question 31

Condensation reaction

Answer 31

When two monomers combine a small molecule is lost. The monomers retain their bonds.