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WalesCombined Science

Unit 2 Chemistry 1: The Earth and its 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 greenhouse gases cause climate change, and what pollutants come from burning fuels?

The greenhouse effect and human causes of climate change, the products of combustion, and the pollutants from burning fuels and their effects.
A focused answer to the WJEC GCSE Science Double Award Unit 2 topic on climate and air quality, covering the greenhouse effect and human-caused climate change, the products of complete and incomplete combustion, and the pollutants from burning fuels.
9 min answer →

What is the limestone cycle, and how is limestone used to make useful materials?

Thermal decomposition of limestone, the reactions of the limestone cycle, and the uses of limestone, quicklime, slaked lime and cement.
A focused answer to the WJEC GCSE Science Double Award Unit 2 topic on limestone, covering thermal decomposition, the reactions of the limestone cycle, and the uses of limestone, quicklime, slaked lime and cement.
9 min answer →

What is the atmosphere made of today, and how did it change over the Earth's history?

The composition of the present-day atmosphere and how the early atmosphere changed, including the roles of oceans, plants and the early volcanic atmosphere.
A focused answer to the WJEC GCSE Science Double Award Unit 2 topic on the atmosphere, covering the composition of the present-day atmosphere and how it evolved from the early volcanic atmosphere through the role of the oceans and photosynthesis.
9 min answer →

How is drinking water made safe, and what does it mean for a substance to be soluble?

The treatment of water to make it safe to drink, the testing of water purity, and solubility including the idea of saturated solutions.
A focused answer to the WJEC GCSE Science Double Award Unit 2 topic on water, covering the stages of water treatment, testing water purity, and solubility including dissolving, saturated solutions and how temperature affects solubility.
9 min answer →