Destruction from the sky🌧
- Hydrocarbon fuels naturally contain some atoms of sulfur. When the fuels burn, the sulfur atoms are oxidised to sulfur dioxide.
- Sulfur dioxide reacts with oxygen and water vapour and becomes sulfuric acid. This forms acid rain.
- The sulfur dioxide gas is usually carried away in the air and falls as acid rain far away from where it was made.
- Acid rain damages buildings, trees, life in streams and ponds, washes valuable minerals from the soil and releases toxic metals.
- When acid rain falls on trees it damages the leaves. The leaves don not photosynthesise efficiently and eventually the tree dies.
- Acid rain causes damage to the surface of limestone structures as it reacts with the calcium carbonate in limestone.
The UK government has pledged to reduce sulfur dioxide emmisions.
- removing sulfur from fuels before they are burned
- trapping sulfur dioxide released after burning fuels
- swapping to fuels with lower sulfur content, such as low low sulfur coal and methane
Climate change and the greenhouse effect🌏
In I/GCSE Chemistry, you will also be asked how certain gases contribute to global warming and climate change.
- Some gases in the atmosphere act like a blanket around the Earth and prevent heat from escaping into space. This warming effect is essential for life on the planet.
- Gases that can do this are called greenhouse gases. Important examples are carbon dioxide, water vapour and methane.
- The temperature of the planet may be affected by changes in the solar activity and changes in amounts of greenhouse gases in the atmosphere.
Humans have increased the amount of carbon dioxide in the atmosphere by burning hydrocarbons and by cutting down and burning forests. Scientists are experimenting with ways to reduce the amount of carbon dioxide and other greenhouse gases.
The warm Earth radiates infrared radiation out towards space. Greenhouse gases absorb this radiation and so trap the energy on the planet. This increases the global temperature (the greenhouse effect).
There is a correlation between the amount of carbon dioxide in the atmosphere and the temperature of the Earth.
Most scientists consider that the rise in the Earth's temperature has been caused by human activities, which have increased the level of carbon dioxide in the atmosphere.
Drafted by Catrina (Chemistry)