Sample Activity of Integration – Carbon in the environment Revision Questions

1. State what is meant by the following terms:

 (i) Fuel

(i) Fossil fuel.

b) The world has not yet discovered the perfect fuel”. Do you agree with this statement?

2. Carbon dioxide is a greenhouse gas. Explain what this means

b) What might happen if the level of greenhouse gases in the atmosphere rises?

c) Suggest some ways in which we could stop this happening.

3. Discuss the statement: ‘ Wood charcoal making in Uganda has done more harm than good.

4. Natural gas, petrol and paraffin are obtained from crude oil and are described as non – renewable fuels.

a) State what is meant by the term ‘ non – renewable ‘.

b) Name the process by which natural gases, petrol and paraffin can be obtained from crude oil. Give a reason for your answer.

c) State one use of each of the natural gases, petrol and paraffin

d) Name one other fuel that can be obtained from crude oil.

5. Increase in carbon dioxide levels could lead to the extinction of some species of living organisms. Explain why.

6a) Diamond and graphite are allotropes of carbon. What does the statement mean?

b) Why is diamond so hard?

c) Using necessary drawings, explain why diamond and graphite have different properties?

7. The results of testing five samples of water from different areas are shown in the table below. The soap solution was gradually added to 25 cm³ of each sample of water while shaking until permanent lather was obtained.

a) State with reasons which water sample (s):

 (I) is / am permanently hard. ( ) is / are temporarily hard.

(ii) Contains both temporary and permanent hardness.

b) Name a compound which could be present in:

 (I) sample S but not in sample T.

 (II) sample R.

C) Explain how the compound you have named in (b) (i) gets into the water.

 d) Write a word equation to show the effect of heat on the substance named in (b) (1).

 e) Name one method that can be used to reduce the amount of soap solution required to form permanent lather with water sample T.

 f) Suppose you are an analytical chemist working for an environmental health organization. You have been given a sample of water which is thought to have been contaminated by one of the salts that cause hardness in water:

 (i) Describe how you could confirm the presence of the type of water hardness by simple chemical tests.

(ii) Write a report on what pieces of advice the organization should give to the community.

g) When soap solution was added to a sample of water, a white precipitate was formed. But when the soap solution was added to another portion of the water that had been boiled, no precipitate was formed. Explain. (Your answer should include equations where possible.)

8. Discuss the statement: ‘ Use of wood charcoal as a source of energy should be preferred to use of fossil fuels.

9a) Complete the following word equation:

Calcium carbonate + dilute nitric acid → ……………..

b) Briefly describe how the gaseous product in (a) can be identified in the laboratory

c) One of the uses of carbon dioxide is dry ice used as a refrigerant.

 What:

 (i) Properties make it a better refrigerant than other substances?

(ii) Are some of the other uses of carbon dioxide?

10. Three forms of carbon are graphite, diamond and wood charcoal.

a) State two structural differences between graphite and diamond.

b) Suggest reasons why:

 (i) Graphite is used to make pencil nibs.

 (ii) Diamond is used to make earrings.

                (iii) Wood charcoal is used in gas masks.

 c) Describe briefly how it can be shown by chemical means that both graphite and diamond contain carbon atoms. Your answer should include word equations where necessary.