C1 experiments

Question 1

Describe an experiment for cracking hydrocarbons. (Equipment)

Answer 1

Mineral wool soaked in paraffin, Bunsen burner, boiling tube, porcelain chips, delivery tube and a gas jar.

Question 2

Describe an experiment used for cracking hydrocarbons.

Answer 2

1) Heat the paraffin and a few seconds later heat the porcelain chips. Do this until the paraffin vaporises and the porcelain glows red.
2) The vaporised paraffin cracks as it passes over the heated porcelain.
3) The smaller alkanes and alkenes travel down the delivery tube. The smallest ones are gasses that are collected in the gas jar.
4)

Question 3

Test for alkenes in cracking hydrocarbons experiment?

Answer 3

You can show the gas in the jar contains alkenes because it de colourises bromine water.

Question 4

What are the conditions needed for cracking?

Answer 4

Heat and a catalyst. In industry vaporised hydrocarbons are passed over a powdered catalyst at 400-700 degrees. Silicon dioxide and aluminium oxide are used as catalysts. In the lab use porcelain chips as a catalyst.

Question 5

Describe an experiment to investigate the proportion of oxygen in an atmosphere?

Answer 5

1) When copper is heated it reacts with oxygen in the air to make copper (I I) oxide - so the reaction uses up oxygen.
2) If you heat up excess copper in a tube and pass air over it with two syringes, the markers on the syringes can tell you how much oxygen is used.
3) About one fifth of the air should be oxygen.

Question 6

Describe a test for the effectiveness of indigestion tablets?

Answer 6

1) Crush up the tablet and dissolve it in water in a conical flask.
2) Add three drops of indicator to the flask which will change colour when neutralised.
3) Fill a burette with hydrochloric acid and add to the conical flask.
4) When the indicator changes colour the alkali has been neutralised. Read the volume of acid used on the burette for effectiveness.

Question 7

Describe the calorimetric method (measures the energy content of fuels)

Answer 7

1) It is important to make as much heat as possible when heating up the water. Use a screen the protect against draughts.
2) Put fuel into a spirit burner and weigh it. Then measure out water into copper calorimeter. Heat up the water until a 20-30 oC increase.
3) Reweigh the fuel and spirit burner.

Question 8

Calorimetric method (equipment).

Answer 8

Screen
Copper calorimeter 
Insulating lid - to reduce heat loss 
Thermometer 
Spirit burner