Collection of Gases

1© 2023 Marshall Cavendish Education Pte Ltd

Chapter 1
Experimental
Chemistry

Chemistry Matters
for GCE ‘O’ Level

2

Recap

• SI units are used as a common standard for recording physical quantities in science.

• Other units are also used to measure physical quantities.

• Different apparatus are used depending on the range and accuracy of the measurement required.

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2

Recap

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Match

Match the following apparatus to the names.

pipette

Burette

Measuring cylinder

Volumetric flask

• pipette

• Burette

• Measuring cylinder

• Volumetric flask

4

Chapter 1 Experimental Chemistry

• 1.1 How Are Physical Quantities Measured?
• 1.2 How Are Gases Collected?
• 1.3 How Are Substances in Mixtures Separated?
• 1.4 How Can the Purity of Substances Be Determined?

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5

1.2 How Are Gases Collected? (Part 1)

Learning Outcome(s)
• Suggest suitable apparatus for the drying and collection of gases.

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6

Capture Interest

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7

Gases

Where can you find gases?

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Open Ended

Where can you find gases?

8

Construct
Understanding

Let's watch a video on Edpuzzle. Go on to Google Classroom. - End this part of lesson. Use Notes Page 14.

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5

1.2 How Are Gases Collected? (Part 2)

Learning Outcome(s)
• Suggest suitable apparatus for the drying and collection of gases.

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Multiple Choice

Oxygen gas was prepared from hydrogen peroxide and collected as shown.

The first few tubes of gas were rejected because the gas was contaminated by

• water vapour

• hydrogen peroxide

• hydrogen

• nitrogen

Open Ended

What were some thoughts that you have about conducting an experiment to collect gas?

9

1.2 How Are Gases Collected?

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Textbook

Page 7

Methods for Collecting Gases

Multiple Choice

Carbon dioxide can collected by displacement of water. Why?

• Carbon dioxide is insoluble in water.

• Carbon dioxide is soluble in water.

• Carbon dioxide is denser than air.

• Carbon dioxide is less dense than air.

Multiple Choice

Hydrogen chloride can be collected by displacement of water. True or false?

• True

• False

Multiple Choice

Ammonia cannot be collected by displacement of water. Why?

• Ammonia is insoluble in water.

• Ammonia is soluble in water.

• Ammonia is denser than air.

• Ammonia is less dense than air.

10

1.2 How Are Gases Collected?

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Textbook

Page 7

Methods for Collecting Gases

Multiple Choice

Oxygen is collected by downward delivery. Why?

• Oxygen is insoluble in water.

• Oxygen is soluble in water.

• Oxygen is denser than air.

• Oxygen is less dense than air.

11

1.2 How Are Gases Collected?

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Textbook

Page 7

Methods for Collecting Gases

Multiple Choice

Hydrogen is collected by upward delivery. Why?

• Hydrogen is insoluble in water.

• Hydrogen is soluble in water.

• Hydrogen is denser than air.

• Hydrogen is less dense than air.

Multiple Select

Methane is insoluble in water and has M_r of 16. Which methods can be used to collect methane?

Multiple Choice

A gas, X, is less dense than air and insoluble in water.

Which method cannot be used to collect the gas?

• A

• B

• C

• D

11

1.2 How Are Gases Collected?

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Textbook

Page 7

Methods for Collecting Gases

Multiple Choice

The volume of gas produced by the reaction needs to be measured. What is the missing apparatus X?

• burette

• pipette

• test tube

• gas syringe

12

1.2 How Are Gases Collected?

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Textbook

Page 7

Methods for Drying Gases

13

1.2 How Are Gases Collected?

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Textbook

Page 7

Methods for Drying Gases

14

1.2 How Are Gases Collected?

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Textbook

Page 7

Methods for Drying Gases

Multiple Choice

Which of the following drying agents would be suitable to dry a moist sample of hydrogen chloride(acidic) gas?

• dilute nitric acid

• concentrated sulfuric acid

• calcium oxide

• calcium carbonate

Multiple Select

Which of the following drying agents would be suitable to dry a moist sample of ammonia (alkaline property) gas?

• quicklime (calcium oxide)

• concentrated sulfuric acid

• aqueous sodium hydroxide

• concentrated ethanoic acid

15

Consolidate
Learning

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16

Let’s Practise 1.2

Check your understanding by trying
out the question(s).

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Textbook

Page 8

Multiple Select

Gas X is less dense than air and is insoluble in water. Suggest a method that can be used to collect gas X.

• Displacement over water

• Upward delivery

• Downward delivery

• gas syringe

Multiple Select

Gas Y reacts with acids. Name one drying agent that can be used on Gas Y.

• concentration sulfuric acid

• fused calcium chloride

• quicklime

18

Summary of Lesson 1.2

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• ​Gases can be collected via different methods, depending on their
  physical properties.

• Some gases may require drying before they can be collected.