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Essential Chemistry for IGCSE - Air And Water (Section 8)

1
What is 'denitrification' in the context of the nitrogen cycle?
Answer
(C)
The process by which nitrogen compounds are broken down to release nitrogen gas into the atmosphere.
2
Which of the following statements is true regarding the role of oceans in the carbon cycle?
Answer
(C)
Oceans store a large amount of carbon.
3
What kind of reaction occurs when the zinc protects the steel?
Answer
(D)
A sacrificial reaction
4
Which of the following is an example of a product formed by burning fossil fuels?
Answer
(C)
Water
5
What is formed when iron rusts?
Answer
(A)
Iron oxide
6
What is the main source of energy in most organisms?
Answer
(B)
Glucose
7
Which component of air is NOT a major gas?
Answer
(D)
Water vapor
8
Which of the following is a characteristic of the carbon reservoir in the atmosphere?
Answer
(D)
The amount of carbon in it is increasing.
9
What process is described in the equation: CO2 + H2O -> C6H12O6 + O2 ?
Answer
(C)
Photosynthesis
10
How is the air dried in the process of fractional distillation?
Answer
(B)
By passing it through a drying agent.
11
What is the primary source of sulfur dioxide in the atmosphere?
Answer
(B)
Burning of fossil fuels.
12
What is a key component of 'smog', mentioned in the Air Pollution section?
Answer
(C)
Sulfur dioxide
13
What kind of effect does global warming have on the sea level?
Answer
(A)
The sea level increases