Exam code: 0620 & 0971
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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Which of the following statements regarding the uses of water are correct?
1 | Water in industry is used as a solvent and as a coolant. |
2 | All water used in industry is safe for human consumption. |
3 | Water in the household may contain dissolved salts. |
4 | Water in the household is used for sanitation and cooking. |
1, 3 & 4
1, 2 & 4
2, 3 & 4
1 & 4 only
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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 statement describing a treatment step and its purpose is incorrect?
Filtration is used to remove dissolved solids.
Carbon filtration is used to remove tastes and odours.
Sedimentation is used to remove mud and sand.
Chlorination is used to kill bacteria.
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What essential plant nutrients do fertilisers supply?
A | phosphorus | calcium | nitrogen |
B | iron | nitrogen | magnesium |
C | nitrogen | potassium | phosphorus |
D | potassium | calcium | nitrogen |
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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 pair of substances would make an NPK fertiliser?
ammonium phosphate and potassium chloride
calcium phosphate and potassium chloride
ammonium sulfate and potassium nitrate
potassium nitrate and calcium carbonate
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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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Ammonia and sulfuric acid can react in the lab to make ammonium sulfate fertiliser.
What is the formula of the product?
NH3SO4
NH4SO4
(NH4)2SO4
(NH3)2SO4
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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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Fertilisers provide three essential elements required for plant growth.
Which substances will make a salt that will contain two of these essential elements?
1 ammonia and nitric acid
2 potassium hydroxide and sulfuric acid
3 ammonia and phosphoric acid
4 potassium hydroxide and nitric acid
1 and 2
1 and 3
2 and 4
3 and 4
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Which substances lead to 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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1 markDifferent fertilisers contain the essential elements needed for plant growth in varying quantities.
Which fertiliser compound contains the highest percentage by mass of the essential elements needed for growth?
[Relative atomic masses, Ar: H = 1; N = 14; O = 16; P = 31; S = 32; K = 39; Ca = 40]
(NH4)2SO4
NH4NO3
K2SO4
Ca3(PO4)2
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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 | 0.03 |
Y | 7.0 | 100.0 | 0.00 |
Z | 6.3 | 100.5 - 100.6 | 0.02 |
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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