A student added anhydrous copper(II) sulfate to a test tube containing an aqueous solution.
Which row correctly describes the colour change the student observed?
|
before addition |
after addition |
|
|
A |
white |
pink |
|
B |
white |
blue |
|
C |
blue |
white |
|
D |
pink |
blue |
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During the treatment of ground water, large insoluble particles are allowed to settle to the bottom of a tank.
What is this process called?
Sedimentation
Anaerobic digestion
Screening
Chlorination
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There are many steps involved when treating water.
Which of the answers below is the incorrect reason for the treatment step being carried out?
| Treatment | Explanation | |
| A | filtration | to remove dissolved solids |
| B | carbon filtration | to remove tastes and odours |
| C | sedimentation | to remove mud and sand |
| B | chlorination | to kill bacteria |
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Potable water is produced from a water source near a country spring as shown in the flow diagram.
Which processes occur at P and Q?
|
P |
Q |
|
|
A |
chlorination |
filtration |
|
B |
chlorination |
distillation |
|
C |
filtration |
distillation |
|
D |
filtration |
chlorination |
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Which is the correct reason for carrying out each step when treating water?
| Adding carbon | Chlorination | Sedimentation | |
| A | kill microbes | remove salts | remove solids |
| B | remove salts | remove odours | kill microbes |
| C | remove odours | kill microbes | remove solids |
| D | remove odours | remove solids | remove salts |
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Which row correctly identifies the substance based on the experiment and observations carried out?
| Experiment | Observations | Identity of bold substance | |
| A | Pink crystals are heated | The crystals turn blue and steam is given off | anhydrous cobalt(II) chloride |
| B | Water is added to a white solid | The white solid turns blue | anhydrous copper(II) sulfate |
| C | Blue crystals are heated | The crystals turn white and steam is given off | anhydrous cobalt(II) chloride |
| D | Water is added to a blue solid | The blue solid turns pink | hydrated copper(II) sulfate |
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