Senior Secondary (HKDSE) · Chemistry

Atmosphere composition & testing O₂: Practice Questions

5 multiple-choice questions marked as you go, and 3 written questions with worked solutions. All on Atmosphere composition & testing O₂.

8 questions12 marksFree, no account

Question 1

1 mark

In the industrial separation of air, which physical property is primarily utilized to separate oxygen and nitrogen during fractional distillation?

Question 2

1 mark

A student uses the setup shown below to determine the percentage of oxygen in a 100 cm\(^3\) sample of air. The air is passed over excess heated copper until the volume becomes constant.

Which of the following represents the most likely color change observed in the combustion tube and the final volume of gas (measured at room temperature)?

Question 3

1 mark

In the industrial fractional distillation of air, which of the following statements correctly identifies the reason for a specific procedural step or the physical behavior of the components?

Question 4

1 mark

A student is given a test tube containing a colorless gas and is asked to perform a chemical test for oxygen. Which of the following procedures and observations is correct?

Question 5

1 mark

In the industrial separation of air, why is the incoming air passed through a series of filters and then treated with concentrated sodium hydroxide solution before being liquefied?

Question 6

2 marks

Identify the noble gas that is the third most abundant component in unpolluted dry air and state its approximate percentage by volume.

Write your answer out first, then check it against the worked solution.

Question 7

3 marks

When a sample of air is passed over excess heated copper turnings in a gas syringe system, the volume of the gas decreases by approximately 21%. Explain the chemical property of oxygen that allows it to be removed from the air in this manner.

Write your answer out first, then check it against the worked solution.

Question 8

2 marks

When identifying oxygen gas in the laboratory, explain why a glowing splint is used instead of a burning splint to differentiate it from other common gases like nitrogen or carbon dioxide.

Write your answer out first, then check it against the worked solution.

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