Gases In The Atmosphere
Overview
The air you are breathing right now has barely changed its recipe in 200 million years. Around four-fifths is nitrogen, one-fifth is oxygen, and a handful of trace gases make up the rest. Yet one of those trace gases, carbon dioxide, is reshaping the planet's climate at a pace scientists can measure in real time.
In this lesson you will learn the composition of dry air, measure the percentage of oxygen using a practical method, describe the combustion of key elements in oxygen, explore thermal decomposition as a source of carbon dioxide, and understand why rising CO2 levels contribute to climate change through the greenhouse effect.
Objectives
- know the approximate percentages by volume of the four most abundant gases in dry air
- understand how to determine the percentage by volume of oxygen in air using experiments involving the reactions of metals (e.g. iron) and non-metals (e.g. phosphorus) with air
- describe the combustion of elements in oxygen, including magnesium, hydrogen and sulfur
- describe the formation of carbon dioxide from the thermal decomposition of metal carbonates, including copper(II) carbonate
- know that carbon dioxide is a greenhouse gas and that increasing amounts in the atmosphere may contribute to climate change
- practical: determine the approximate percentage by volume of oxygen in air using a metal or a non-metal
Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Gases In The Atmosphere. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- What is the approximate percentage of nitrogen in dry air? A) 21% B) 78% C) 0.9% D) 0.04% Answer: B
- Which gas turns limewater milky? A) Oxygen B) Nitrogen C) Carbon dioxide D) Hydrogen Answer: C
- What is produced when magnesium burns in oxygen? A) Magnesium hydroxide B) Magnesium carbonate C) Magnesium oxide D) Magnesium chloride Answer: C
- Which of the following is NOT a greenhouse gas? A) Carbon dioxide B) Methane C) Water vapour D) Nitrogen Answer: D
- Thermal decomposition of copper(II) carbonate produces: A) Copper and carbon dioxide B) Copper(II) oxide and carbon dioxide C) Copper(II) oxide and carbon monoxide D) Copper(II) hydroxide and carbon dioxide Answer: B
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
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