Question 1 (02 CT1)

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Question 2 (MY 02)

(a) Draw structures for each of the following molecules and state whether each molecule would be polar or non-polar.(i) Tetrachloromethane. (ii) Ammonia.

(iii) Sulfur Trioxide (iv) Phophorus pentafluoride

(b) Acid rain has affected the living and non-living environment.(i) Name two gases added to the atmosphere by human activities that contribute to acid

rain. (2 marks)

(ii) State an activity that would produce each of these gases. (2 marks)

(iii)

(1) Describe an effect of acid rain on the living environment. ( 1m)

(2) Describe with an equation an effect of acid rain on the non-living environment.

(3 marks)

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Question 3

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Question 4

8 marks

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Question 5

Question 6 (03 MY)

(a) Draw structures for each of the following molecules and state whether each molecule would be polar or non-polar.(i) Sulfur trioxide (ii) Phosphorus triiodide.

(iii) Boron tribromide (iv) Selenium hexafluoride

(b) All rain is acidic, but not all rain is called ‘acid rain’.(i) Explain with an equation why rain is naturally acidic and hence define acid rain. (3 marks)

(ii) Sulfur trioxide is one of the gases that contribute to acid rain. With the aid of equation, show how another oxide of sulfur lead to the formation of acid rain. (2 marks)

(iii)

Explain with an equation what happens when “acid rain” comes in contact with metal bridges. (3 marks)

Question 7 (03 trial)

(a) There is a certain degree of interaction between the greenhouse effect, acid rain, and photochemical smog.

(i) State one source of the following pollutants:(1) hydrocarbons (1 mark)

(2) CFCs (1 mark)

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(b) The graph below shows the concentration of nitrogen dioxide and ozone on a warm sunny day in a typical large city like Adelaide.

concentration O3

NO2

6am noon 6pm midnight Time of the day

(i) Suggest a reason why are there two peaks in the nitrogen dioxide concentration? (1 mark)

(ii) Explain with aid of equations why the ozone concentration peaks in the middle of the day and decline in late afternoon? (4 marks)

(iii) The ozone can react to form secondary pollutants. Name one such pollutant that is

found in the photochemical smog. (1 mark) Question 8 (CT1 04)

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(ii) Ammonia itself is agood fertilizer with high solubility in water. State one disadvantage of using ammonia gas rather than ammonium nitrate as fertilizers. (1 m)

Question 9

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Question 10

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Question 11 (CT1 03)

shape

Question 12

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Question 13

Question 14 (MY 04)

The element nitrogen is about 78% of our atmosphere; it exists as stable diatomic molecules; it is vital to plant growth but in the molecular form it is not able to be used by plants.

(a) Draw the structural formula for the nitrogen molecule and hence explain why it is stable. (3 marks)

(b) Plant can absorb nitrogen only when it is converted to a certain ion. Write the formula of this ion. (1 mark)

(c) Describe, (including equations) one natural way in which atmospheric nitrogen may be changed to a form useable by plants. (4 marks)

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