Exam code: 5070
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 |
D | chlorination | to kill bacteria |
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Four substances that may be found in water from natural sources are listed.
dissolved oxygen
metal compounds such as calcium and magnesium ions
microplastics
nitrates and phosphates
Which substances are beneficial to aquatic life?
1 and 4
1 and 2
2 and 3
3 and 4
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Four substances may be found in water from natural sources.
Which substance causes disease in people who drink the water?
dissolved oxygen
microbes from sewage
nitrate from fertilisers
phosphate from detergents
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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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Mineral water contains dissolved salts such as magnesium chloride. Which one of the following statements about mineral water is correct?
Mineral water boils at slightly above 100 °C.
Mineral water is pure water.
Mineral water boils at exactly 100 °C.
Another name for mineral water is fizzy water.
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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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Nitrate and phosphate are both found in water from natural sources.
Which row correctly gives a substance and its source?
substance | source | |
|---|---|---|
A | nitrate | fertilisers and detergents |
B | phosphate | fertilisers only |
C | phosphate | fertilisers and detergents |
D | nitrate | detergents only |
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A student needs water of high purity to make up a solution for a reaction.
The student is told to use distilled water rather than tap water.
Which statement gives the reason for this?
Distilled water has a higher boiling temperature than tap water.
Distilled water has been chlorinated and tap water has not.
Tap water is acidic and distilled water is alkaline.
Distilled water contains fewer dissolved substances than tap water.
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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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Which substances lead to the deoxygenation of water?
1 NH4NO3
2 Pb
3 Mg
4 Ca3(PO4)2
2 and 4
1 and 2
3 and 4
1 and 4
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Four water samples, W, X, Y and Z, were analysed in the laboratory to measure pH, boiling point, and the amount of dissolved solids.
The sources of water were:
pure water
tap water
acidic rain
sea water
The results are shown in the table below.
Water sample | pH | Boiling point / °C | Mass of dissolved solids in 20 cm3 of water / g |
W | 8.2 | 101.3 - 101.5 | 0.72 |
X | 4.2 | 100.2 - 100.3 | 0.01 |
Y | 7.0 | 100.0 | 0.00 |
Z | 6.3 | 100.5 - 100.6 | 0.04 |
Which are the correct identities of water samples W, X, Y and Z?
W | X | Y | Z | |
A | acidic rain | pure water | tap water | sea water |
B | pure water | tap water | sea water | acidic rain |
C | tap water | sea water | acidic rain | pure water |
D | sea water | acidic rain | pure water | tap water |
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Four samples of water are tested.
The table shows the temperature at which each sample melts and the temperature at which each sample boils.
sample | melting temperature / °C | boiling temperature / °C |
|---|---|---|
A | 0.0 | 100.0 |
B | −1.6 to −0.8 | 100.4 |
C | −0.5 to −0.2 | 100.1 |
D | −2.4 to −1.6 | 100.6 |
Which sample is pure water?
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Four statements are made about substances found in water from natural sources.
1 | Some metal compounds in the water are toxic. |
2 | Some metal compounds in the water provide essential minerals for life. |
3 | Nitrate in the water leads to deoxygenation of the water. |
4 | Dissolved oxygen in the water is harmful to aquatic life. |
Which statements are correct?
1 and 3 only
2 and 4 only
1, 2 and 3
1, 2, 3 and 4
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