Organic chemistry

Question 1

Hydrocarbon

Answer 1

Only contains Hydrogen and Carbon

Question 2

Alkane

Answer 2

Contains only single bonds
CnH2n+2

Question 3

Alkene

Answer 3

Contains at least one double bond
CnH2n

Question 4

Saturated

Answer 4

Contains only single bonds

Question 5

Unsaturated

Answer 5

Contains at least one double bond between carbon atoms

Question 6

Parts of a name

Answer 6

1. How many carbon atoms- meth, eth, prop, but
2. Alkane or Alkene- ane or ene

Question 7

Butane [3]

Answer 7

C4H10
Only single bonds
Alkane

Question 8

Ethene [3]

Answer 8

C2H4
Contains a double bond
Alkene

Question 9

of carbon atoms

Meth, eth, prop, but

Answer 9

Meth- 1
Eth- 2
Prop- 3
But- 4

Question 10

Ethanol [2]

Answer 10

C2H6O or C2H5OH
Alcohol (contains OH)

Question 11

Complete combustion

Answer 11

Enough oxygen

Question 12

Products of complete combustion

Answer 12

Carbon dioxide + Water
CO2 + H2O

Question 13

Fractional Distillation products

Answer 13

Fuel gases, petrol, kerosene, diesel, fuel oil, bitumen

Question 14

Suggest 3 reasons why bitumen is not used as a fuel
[3]

Answer 14

• Too high a boiling point
• Not flammable
• Viscous (doesn’t flow easily)

Question 15

How can bromine be used to distinguish between alkanes and alkenes? [2]

Answer 15

• Alkanes do not react with bromine (as they are saturated)
• Alkenes do react with bromine and the orange bromine with becoming discoloured (double bond opens and bonds with the bromine)

Question 16

Ethene reaction with hydrogen.
[2]

Answer 16

• Forms ethane
• C2H4 + H2 –> C2H6

Question 17

Ethene reaction with bromine
[2]

Answer 17

• Forms a haloalkane
• C2H4 + Br2 –> C2H4Br2

Question 18

Ethene reaction with steam
{2}

Answer 18

• Forms ethanol (alcohol)
• C2h4 + H2O –> C2H5OH

Question 19

What is an addition reaction? [1]
Give an example of one [1]

Answer 19

• A reaction where there are two reactants and then there is one product
• Ex. Propene + bromine –> Biopropane ( halo alkane)

Question 20

Give 2 reasons why large hydrocarbon molecules are cracked to produce smaller hydrocarbon molecules
[2]

Answer 20

• There is a higher demand for smaller hydrocarbon molecules
• They are better fuels (easier burning)

Question 21

Fuels

Answer 21

Release heat energy when they combust (burn in oxygen)

Question 22

Symbol equation for cracking:
decane –> octane + ethene

Answer 22

C10H22 –> C8H18 + C2H4

Question 23

Name 3 fossil fuels

Answer 23

Coal, natural gas, petroleum

Question 24

What is meant by homologous series? [3]

Answer 24

A family of similar compounds.
The compounds in a homologous series have the same general formula and a gradual change in physical properties.
Each compound differs from the next by a CH2 group.

Question 25

How many bonds can carbons form? [1]

Answer 25

4

Question 26

Which type of bonds do alkanes form?

Answer 26

Single, covalent

Question 27

Name the products of fractional distillation of petroleum [5]

Answer 27

Refinery gas- bottled gas for cooking and heating
Gasoline fraction- for fuel (petrol) in cars
Naphtha fraction- the feedstock for making chemicals
Diesel oil/gas oil- for fuel in diesel engines
Bitumen- for road surfaces

Question 28

Name the 2 ways ethanol can be produced.
State an advantage and disadvantage for both. [6]

Answer 28

1. Fermentation
   + cheap, made at 37 degrees c and so not much energy is used
   - Low percentage yield, only about 18% yield of ethanol [3]
2. Ethene and steam reaction (hydration reaction)
   + Continuous process
   + High percentage yield
   - Expensive, high temperature is needed and so uses a lot of electricity [3]

Question 29

Define Polymers

Answer 29

long chain molecules formed
from small units (monomers)

Question 30

What type of polymerisation is used in forming poly(ethene)?

Answer 30

Addition polymerisation

Question 31

Name 2 things necessary when drawing polymers

Answer 31

1. The bonds extend out of the square brackets
2. Add the ‘n’ by the bottom right of the polymer and an ‘n’ on the left hand side of the displayed formula of the alkene

Question 32

State the differences between addition polymerisation and condensation polymerisation. [2]

Answer 32

Addition polymerisation- multiple of the same monomer bonds to form 1 polymer. 2+ reactants and 1 product
Condensation polymerisation- 2 different monomers bond together with the removal of a small molecule (usually water) 2+ reactants and 2 products