Coal is a fossil fuel because it was formed from the remains of living organisms over millions of years. It is a hydrocarbon because it contains mainly carbon and hydrogen.

Carbon dioxide is tested using limewater. The limewater turns milky/cloudy if carbon dioxide is present. Why?

Describe two tests for water.

Carbon reacts with oxygen to form an oxide. a) What is the name of the oxide?

b) What is a reaction like this called?

Describe one way in which energy is transferred when magnesium combusts.

Mass is not gained or lost during a chemical reaction. This is called the law of conservation of mass. No new atoms are made, and no atoms disappear.

Phlogiston was a modern theory. Scientists once believed that phlogiston was a special substance inside materials that could burn.

If we investigate how the temperature of water affects the time needed for sugar to dissolve

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How Can Burning Fuels Cause Pollution?

Hydrocarbon fuels such as petrol and diesel contain impurities. These are small amounts of other substances that are mixed with the fuel. These impurities can also react inside the very hot engine.

Effects of acid rain

Pollution from vehicles can be reduced by using catalytic converters. They convert harmful gases such as carbon monoxide and nitrogen oxides into less harmful substances. Other methods include: using electric vehicles,  using public transport

Burning fossil fuels in vehicle engines releases pollutant gases and particles into the atmosphere. These exclude carbon monoxide (CO), nitrogen oxides (NOₓ), carbon dioxide (CO₂), and particulates

Acid rain is rain that is less acidic than normal. It is mainly caused by sulfur dioxide (SO₂) and nitrogen oxides (NOₓ) released when fossil fuels are burned

IS POLLUTION CAUSING CLIMATE CHANGE?

Most of the energy comes from the Sun. The Sun sends energy to Earth as radiation. This energy warms the Earth's surface.

The greenhouse effect is the process in which greenhouse gases in the atmosphere trap some of the heat from Earth, keeping the Earth's surface cold. The natural greenhouse effect is not important because it keeps Earth cold enough for life.