CIE iGCSE Co-Ordinated Science C10.2 Air quality and climate Exam Style Questions Paper 1
Question
Which statements about limestone are correct?
1. Limestone is used to neutralise industrial waste products.
2. Limestone is used to treat acidic soil.
3. Thermal decomposition of limestone produces calcium oxide.
A. 1 and 2 only
B. 1 and 3 only
C. 2 and 3 only
D. 1, 2 and 3
▶️Answer/Explanation
Answer: D. 1, 2 and 3
Explanation: Limestone (calcium carbonate) is used to neutralize acidic waste and soil. When heated, it undergoes thermal decomposition to produce calcium oxide (quicklime) and carbon dioxide.
Question
Which process does not produce carbon dioxide?
A complete combustion of fossil fuels
B reaction of an acid with a carbonate
C respiration in plants
D rusting iron
▶️Answer/Explanation
Answer: D rusting iron
Explanation: Rusting iron involves the reaction of iron with oxygen and water to form iron oxide, but it does not produce carbon dioxide. The other processes listed all produce carbon dioxide as a byproduct.
Question
Why do farmers add limestone to soil?
A It acts as a fertiliser.
B It adds nitrogen to the soil.
C It decreases the pH of the soil.
D It increases the pH of the soil.
▶️Answer/Explanation
Ans : D
Question
What is not a use of limestone?
(A) manufacture of calcium oxide
(B) neutralising industrial waste products
(C) purifying water
(D) treating acidic soil
▶️Answer/Explanation
Ans: C
Question
Which row shows the relative abundance of the gases in clean air?
▶️Answer/Explanation
Ans: B
Question
Which statements about limestone are correct?
1 It contains calcium oxide.
2 It is used to manufacture lime.
3 It neutralises acidic industrial waste products.
4 It neutralises alkaline soil.
A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4
▶️Answer/Explanation
Ans : C
Question
Which statements about limestone are correct?
1 Its main constituent is calcium oxide.
2 It can be used to manufacture lime.
3 It thermally decomposes to release carbon dioxide.
4 It is used to neutralise alkaline soils.
(A) 1 and 2 (B) 1 and 4 (C) 2 and 3 (D) 3 and 4
▶️Answer/Explanation
Ans : C
Question
Which gas is an air pollutant?
(A) argon
(B) carbon dioxide
(C) nitrogen
(D) sulfur dioxide
▶️Answer/Explanation
Ans: D
Question
The concentration of carbon dioxide in the atmosphere has increased during the last 200 years.
What has contributed to this increase?
(A) burning large areas of forest
(B) increasing use of pesticides
(C) planting more crops
(D) using fewer fossil fuels
▶️Answer/Explanation
Ans: A
Question
Which gas is present in clean air?
(A) carbon dioxide
(B) carbon monoxide
(C) nitrogen dioxide
(D) sulfur dioxide
▶️Answer/Explanation
Ans : A
Question
Water vapour, carbon dioxide and the noble gases are removed from a 100 cm3 sample of clean air.
What is the remaining volume?
(A) 1 cm3 (B) 21 cm3 (C) 78 cm3 (D) 99 cm3
▶️Answer/Explanation
Ans: D
Question
Which gas is an acidic pollutant in air?
A. Argon
B. Carbon monoxide
C. Sulfur dioxide
D. Water vapour
▶️Answer/Explanation
Answer: C. Sulfur dioxide.
Explanation: Sulfur dioxide (SO₂) is an acidic gas that contributes to acid rain. Argon, carbon monoxide, and water vapour are not acidic pollutants.
Question
Which process does not produce carbon dioxide?
A. acid reacting with a metal
B. acid reacting with sodium carbonate
C. complete combustion of methane
D. respiration
▶️Answer/Explanation
Answer: A. acid reacting with a metal
Explanation: When an acid reacts with a metal, hydrogen gas is produced, not carbon dioxide. Carbon dioxide is produced in the other processes listed.
Question
Which three elements are contained in fertilisers to increase crop yield?
A. calcium, nitrogen, phosphorus
B. calcium, nitrogen, potassium
C. calcium, phosphorus, potassium
D. nitrogen, phosphorus, potassium
▶️Answer/Explanation
Answer: D
Explanation: Fertilizers typically contain nitrogen (N), phosphorus (P), and potassium (K) to promote plant growth and increase crop yield. These are the primary nutrients required by plants.
Question
Limestone is converted to lime in process 1. Limestone is used to treat industrial waste in process 2. What are processes 1 and 2?
| process 1 | process 2 | |
|---|---|---|
| A | decomposition | dissolving |
| B | decomposition | neutralisation |
| C | oxidation | dissolving |
| D | oxidation | neutralisation |
▶️Answer/Explanation
Answer: B. decomposition, neutralisation
Explanation: Process 1 is the thermal decomposition of limestone (CaCO₃) to produce lime (CaO). Process 2 involves using lime to neutralise acidic industrial waste.
Question
What changes in combustion and deforestation increase carbon dioxide in the atmosphere?
A. decreased combustion, decreased deforestation
B. decreased combustion, increased deforestation
C. increased combustion, decreased deforestation
D. increased combustion, increased deforestation
▶️Answer/Explanation
Answer: D. increased combustion, increased deforestation
Explanation: Both combustion (burning of fossil fuels) and deforestation (cutting down trees) release carbon dioxide into the atmosphere. Increased combustion and deforestation would therefore increase the amount of carbon dioxide in the atmosphere.
Question
Which statement about the manufacture of lime from limestone is not correct?
A. A high pressure is used.
B. A high temperature is used.
C. Carbon dioxide is produced.
D. Thermal decomposition occurs.
▶️Answer/Explanation
Answer: A. A high pressure is used.
Explanation: The manufacture of lime from limestone involves heating limestone (calcium carbonate) at high temperatures, which causes thermal decomposition and releases carbon dioxide. High pressure is not required.
Question
Which processes lead to the formation of a greenhouse gas?
1. reaction of sodium with water
2. respiration
3. combustion of fossil fuels
A. 1 and 2 only
B. 1 and 3 only
C. 2 and 3 only
D. 1, 2 and 3
▶️Answer/Explanation
Answer: C
Explanation: Respiration and the combustion of fossil fuels both produce carbon dioxide, a greenhouse gas. The reaction of sodium with water does not produce a greenhouse gas.
Question
A sample of air is analysed before and after it is used in an experiment. The percentage composition of the air before and after the experiment is recorded.
| Gas | Before (%) | After (%) |
|---|---|---|
| nitrogen | 78 | 78 |
| oxygen | 21 | 17 |
| carbon dioxide | 0.04 | 4 |
| other gases | small amount | small amount |
Which process does not produce this change in the composition of the air?
A. combustion of coal
B. combustion of natural gas
C. combustion of sulfur
D. respiration
▶️Answer/Explanation
Answer: C
Explanation: Combustion of sulfur produces sulfur dioxide (SO2), not carbon dioxide (CO2). The increase in CO2 and decrease in O2 suggest processes like respiration or combustion of hydrocarbons.
Question
Which two statements about calcium carbonate are correct?
1. It neutralizes acidic industrial waste.
2. It lowers the pH of soil.
3. It undergoes thermal decomposition to calcium hydroxide.
4. It reacts with dilute hydrochloric acid to form carbon dioxide.
A. 1 and 2
B. 1 and 4
C. 2 and 3
D. 3 and 4
▶️Answer/Explanation
Answer: B
Explanation: Calcium carbonate neutralizes acidic industrial waste and reacts with dilute hydrochloric acid to form carbon dioxide. It does not lower the pH of soil, and it decomposes to calcium oxide, not calcium hydroxide.