This question is about gases in the atmosphere.
argon | carbon dioxide | helium | nitrogen | oxygen |
Each gas may be used once, more than once or not at all.
(1)
(1)
(1)
(1)
[1]
[1]
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This question is about gases in the atmosphere.
argon | carbon dioxide | helium | nitrogen | oxygen |
(1)
(1)
(1)
(1)
[1]
[1]
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A teacher uses this apparatus to find the percentage of oxygen in a gaseous mixture of oxygen and argon.
This is the teacher’s method.
The volume of gas decreases as the oxygen reacts with the copper.
Argon is unreactive so does not react with the copper.
The copper powder turns black.
Reading number | Reading on syringe A in cm3 |
Start | 78 |
1 | 70 |
2 | 67 |
3 | 65 |
4 | 63 |
5 | 61 |
6 | 60 |
7 | 59 |
8 | 58 |
9 | 58 |
10 | 58 |
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This question is about gases.
argon | carbon dioxide | hydrogen | nitrogen | oxygen |
(1)
(1)
(1)
(1)
(1)
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This question is about gases in the air.
The pie chart represents the percentages of gases in dry, unpolluted air.
Gases with percentages of less than 1% in air are called trace gases.
☐ | A | hydrogen | |
☐ | B | methane | |
☐ | C | neon | |
☐ | D | nitrogen |
☐ | A | 0.04% | |
☐ | B | 0.9% | |
☐ | C | 21% | |
☐ | D | 35% |
cracking an alkane | |
complete combustion of an alkane | |
reaction between magnesium and hydrochloric acid | |
rusting of iron | |
thermal decomposition of copper(II) carbonate |
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This question is about gases in the atmosphere.
argon carbon dioxide helium nitrogen oxygen |
(1)
(1)
(1)
(1)
(1)
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Air is a mixture of gases.
What is the approximate percentage of nitrogen in air?
(1)
☐ | A | 1 | |
☐ | B | 20 | |
☐ | C | 25 | |
☐ | D | 78 |
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The percentage by volume of oxygen in air can be found by using the rusting of iron. A student sets up this apparatus to measure the volume of oxygen in a sample of air.
An excess of wet iron filings is used. At the start of each experiment, the reading on the syringe is recorded and the apparatus is then left for a week so that the reaction is complete. The reading on the syringe is then recorded again.
Complete the table to show:
syringe reading at start / cm3 | 76 |
syringe reading at end / cm3 | |
volume of oxygen used / cm3 |
(2)
volume of air in conical flask / cm3 | 100 |
volume of air in connecting tube / cm3 | 10 |
original volume of air in syringe / cm3 | 80 |
final volume of air in syringe / cm3 | 43 |
Calculate the percentage of oxygen in air using these results.
percentage of oxygen = ............. %
(3)
decreased | increased | no effect |
Each term may be used once, more than once, or not at all.
(3)
Possible cause | Effect on volume of oxygen used |
wet iron filings not in excess | |
apparatus left for 1 hour instead of 1 week | |
apparatus left in a warmer place for 1 week |
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The approximate percentage of oxygen in air can be determined in the laboratory using this apparatus.
The steps for the method are shown below.
The steps shown are not in the correct order.
Which of the following shows the correct order of the steps above?
(1)
☐ | A | M, K, N, L, O | |
☐ | B | K, M, N, L, O | |
☐ | C | M, N, K, L, O | |
☐ | D | K, M, N, L, O |
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A teacher uses the reaction between phosphorus and oxygen to calculate the percentage of oxygen in air.
She uses this apparatus and excess phosphorus.
The volume of gas in the tube decreases as the phosphorus reacts with oxygen.
The teacher measures the volume of gas in the tube at one-minute intervals.
The table shows the teacher’s results.
Time in minutes | Volume of gas in tube in cm3 |
0 | 48.5 |
1 | 41.0 |
2 | 38.0 |
4 | 37.5 |
5 | 37.0 |
6 | 37.0 |
7 | 37.0 |
(1)
(1)
(3)
percentage = ...........................%
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Carbon dioxide is a gas present in air.
Which statement is not correct about carbon dioxide?
(1)
☐ | A | When bubbled through limewater, carbon dioxide turns limewater cloudy | |
☐ | B | It is produced when copper(II) carbonate undergoes thermal decomposition | |
☐ | C | It is the third most abundant gas in the atmosphere | |
☐ | D | It is a greenhouse gas that contributes to climate change |
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A student uses this apparatus to investigate the effect of heat on different solid metal carbonates.
This is the student’s method:
The student repeats the method using different metal carbonates.
When a metal carbonate is heated a reaction sometimes occurs.
The equation for the reaction is:
metal carbonate → metal oxide + carbon dioxide
1. ...........................................
2. ...........................................
(2)
Metal carbonate | Colour change of solid | Time taken for any change in limewater |
calcium carbonate | remains white | 90 seconds |
sodium carbonate | remains white | no change |
copper(II) carbonate | 50 seconds |
from ...................................... to ...................................
(2)
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Metal carbonates undergo thermal decomposition when heated.
Which is a correct balanced symbol equation for the thermal decomposition of a metal carbonate?
(1)
☐ | A | LiCO3 → LiO + CO2 | |
☐ | B | Mg2CO3 → Mg2O + CO2 | |
☐ | C | CaCO3 + CO2 → CaO | |
☐ | D | CuCO3 → CuO + CO2 |
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Combustion reactions involve a chemical change in which oxygen reacts with elements or compounds to produce oxides.
Which is the correct statement about combustion?
(1)
☐ | A | Combustion reactions are also reduction reactions | |
☐ | B | During the combustion of sulfur, a blue flame is observed and a colourless, poisonous gas is produced | |
☐ | C | All combustion reactions are endothermic | |
☐ | D |
The balanced symbol equation for the combustion of hydrogen is: H2 + O2 → H2O2 |
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