Alkenes and Alkanes

Question 1

What is the formula for Alkanes?

Answer 1

CnH2n+2

Question 2

Why are alkanes saturated?

Answer 2

Because all bonds are occupied and cannot be broken to form new ones.
- There isn’t a double bond with the same atom, that can be broken to form a new bond.

Question 3

What is the formula for alkenes?

Answer 3

CnH2n

Question 4

Why are alkenes unsaturated?

Answer 4

They can make more bonds once the DOUBLE BOND between carbons are broken.

Question 5

What is an alkene + bromine reaction used for?

Answer 5

To test for alkenes.

Question 6

How is an alkene reaction carried out with Bromine

Answer 6

Alkene and bromine are mixed together in a test tube.

• If alkene is present then the solution turn from orange to colourless
• Otherwise, there is no change in colour.

Question 7

What is produced when alkenes and alkanes are burned with oxygen? (Oxidation)

Answer 7

Carbon dioxide + Water

Question 8

How is addition polymerisation carried out?

Answer 8

Double bonds of Alkenes are broken down and new bonds are formed with monomers.

Question 9

What is the formula for polymers?

Answer 9

(CnH2n)n

Question 10

What is the result of condensation polymers?

Answer 10

Reactions between functional groups create water.

Question 11

What is the rule between a condensation polymerisation reaction?

Answer 11

Two reacting monomers have to have two of their own functional groups at either end of the molecule, to create a long change of alternating monomers.

Question 12

What are polymers normally which make them resistant to breaking down?

Answer 12

Non - Biodegradable

Question 13

Why is the burning of plastics excellent and harmful?

Answer 13

• Produces alot of energy

- Produces alot of toxins and releases carbon dioxide

Question 14

What is the advantage of recycling?

Answer 14

Less cure oil has to be used in the production of plastics

Question 15

What is a disadvantage to recycling?

Answer 15

Process releases toxins into the environment

Question 16

What is the formula for alcohol?

Answer 16

CnH2n+1OH

Question 17

What is the formula for Carboxylic acids

Answer 17

Cn-1H2n-1COOH

Question 18

How are carboxylic acids formed?

Answer 18

When alcohols become oxidised

Question 19

How does fermentation create alcohols?

Answer 19

A reaction that uses yeast as a catalyst in converting carbohydrates into alcohol.

• Glucose solution is mixed with yeast
• Mixture is kept at 30-40 degrees
• Mixture is air-tight, to stop it from reacting with oxygen.

Question 20

How do you obtain a concentrated amount of alcohol?

Answer 20

Through fractional distillation
- Ethanol has a lower boiling point than water so when the fraction is heated water stays and ethanol leaves the water as it escapes into another chamber.

Question 21

What is the purpose of burning alcohol in this practice?

Answer 21

To see which one provides more energy.

Question 22

How do you carry out the alcohol burning practical?

Answer 22

1. Pour a constant volume of water into a copper calorimeter
2. Set an alcohol spirit burner underneath the calorimeter
3. Measure the mass of the spirit burner
4. Set fire to the wig of the spirit burner
5. Once the temperature of the water has raised by 20 degrees stop the practical
6. Measure the mass of spirit burner
7. Calculate the change in mass

Question 23

What should you conclude after the alcohol experiment?

Answer 23

The most efficient fuel (alcohol) is the one that raises the temperature with the least mass change.

Question 24

Order of homologous series?

Answer 24

METHANE
ETHANE
PROPANE
BUTANE
PENTANE
HEXANE
HEPTANE
OXANE