Composition & Heating of the Atmosphere is one of 9 topics in the Grade 10 Geography CAPS syllabus, covered across 3 lessons on Study Vault. Below are real practice questions from this topic with full worked answers.
Sample practice questions
Easy
1. Which two gases make up the vast majority (about 99%) of the Earth's dry atmosphere by volume?
Nitrogen and oxygen
Carbon dioxide and methane
Hydrogen and helium
Ozone and argon
Answer: Nitrogen and oxygen — Dry air in the lower atmosphere is approximately 78% nitrogen and 21% oxygen, together making up about 99% of the atmosphere by volume.
Easy
2. The ozone layer is mainly found within which layer of the atmosphere?
The stratosphere
The troposphere
The core of the Earth
Outer space, beyond the atmosphere entirely
Answer: The stratosphere — The ozone layer is found within the stratosphere, roughly 12 km to 50 km above the surface, where it absorbs harmful ultraviolet radiation.
Medium
3. What is the name of the group of human-made chemicals that were historically the main cause of ozone depletion in the stratosphere?
Answer: Chlorofluorocarbons — Chlorofluorocarbons (CFCs), chemicals historically used in refrigeration and aerosols, were the main human-released substances responsible for breaking down ozone molecules in the stratosphere.
