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Chemistry CIE iGCSE:
Air + Water

Page 1


1. The flow chart shows the stages in the treatment of river water to produce drinking water:

River water → sedimentation → process G → process H → drinking water

What are processes G and H?

  Process G Process H
A distillation filtration
B distillation sterilisation
C filtration distillation
D filtration sterilisation
2. The presence of water can be tested for using either anhydrous cobalt(II)chloride or anhydrous copper(II)sulfate. What is the colour change observed if water is present?  
  Cobalt(II)chloride Copper(II)sulfate
A Blue to pink White to blue
B Pink to blue Blue to white
C White to blue Blue to pink
D Blue to white White to blue
3. Which of the following test results would determine that a sample of water is pure?
  • A.   It has a pH of 7
  • B.   It has a boiling point of 100°C
  • C.   It has no taste
  • D.   It changes the colour of anhydrous copper(II)sulfate

4. Which statements about water are correct?

I. Ground water is filtered to remove soluble impurities
II. Ground water is treated with chlorine to kill bacteria
III. Drinkable water may contain dissolved salts
  • A.   I and II only
  • B.   I and III only
  • C.   II and III only
  • D.   I, II and III
5. The pie chart shows the approximate percentage of the three most abundant gases in dry air in today’s atmosphere.


The gases represented by X, Y and Z are:

atmosphere gases pie chart
  X Y Z
A oxygen carbon dioxide nitrogen
B nitrogen Carbon dioxide oxygen
C oxygen argon nitrogen
D nitrogen argon oxygen

 Q6-9 Combustion of hydrocarbon fuels can produce carbon dioxide, carbon monoxide, sulfur dioxide and oxides of nitrogen. Particulates may also be released into the atmosphere.


6. The correct word equation for the complete combustion of a hydrocarbon fuel is ..

  • A.  fuel  + oxygen  carbon dioxide  +  water
  • B.  fuel  + oxygen  carbon dioxide  +  hydrogen
  • C.  fuel  + oxygen  carbon monoxide  +  water
  • D.  fuel  + oxygen  carbon monoxide  +  hydrogen
7. Carbon monoxide is dangerous because it ..
  • A.  causes global warming
  • B.  causes acid rain
  • C.  limits the blood from carrying oxygen
  • D.  limits the blood from carrying carbon dioxide
8. Which substance does NOT cause respiratory problems in humans?
  • A.   particulates
  • B.   carbon dioxide
  • C.   sulfur dioxide
  • D.   oxides of nitrogen
9. Which two gases produced from the burning of petrol in car engines contribute to damage to buildings as a result of acid rain?
  • A.   carbon monoxide and carbon dioxide
  • B.   carbon dioxide and sulfur dioxide
  • C.   sulfur dioxide and oxides of nitrogen
  • D.   oxides of nitrogen and carbon monoxide
10. In which process is carbon dioxide NOT formed?


Carbon dioxide molecule

Jacek FH | CC-BY-SA 3.0

  • A.   burning fossil fuels
  • B.   respiration
  • C.   adding acid to marble chips
  • D.   photosynthesis