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WalesChemistry

Unit 1: The Earth, Atmosphere and Resources

4 dot points across 4 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How do human activities change the climate and the quality of the air we breathe?

Greenhouse gases and climate change, the combustion products that pollute the air, and the problems each pollutant causes.
A focused answer to WJEC GCSE Chemistry topic 1.4 on climate change and air quality, covering greenhouse gases and global warming, the gases released when fuels burn, and the environmental problems caused by carbon monoxide, sulfur dioxide and oxides of nitrogen.
9 min answer →

Why is limestone such a useful rock, and what is the limestone cycle?

Limestone and its uses, the thermal decomposition of calcium carbonate, the reactions of the limestone cycle, and building materials made from limestone.
A focused answer to WJEC GCSE Chemistry topic 1.6 on limestone, covering its uses, the thermal decomposition of calcium carbonate to make quicklime, the limestone (lime) cycle, and the building materials cement, mortar and concrete.
9 min answer →

What is the air made of today, and how did the atmosphere change over billions of years?

The composition of today's atmosphere, the early atmosphere, and how the proportions of carbon dioxide and oxygen changed over geological time.
A focused answer to WJEC GCSE Chemistry topic 1.4 on the atmosphere, covering the composition of air today, the volcanic early atmosphere, and how the levels of carbon dioxide and oxygen changed to give the atmosphere we have now.
9 min answer →

How is drinking water made safe, and how do substances dissolve in water?

The water cycle, treatment of water for drinking, the test for water, and solubility including the difference between dilute and concentrated solutions.
A focused answer to WJEC GCSE Chemistry topic 1.3 on water, covering the water cycle, how water is treated to make it safe to drink, the chemical test for water, and solubility including solutes, solvents and saturated solutions.
9 min answer →