Greenhouse Effect

Gases and acid rain.


Global warming may be the long term consequence of using fossil fuels but the short term effects are felt now. Acid rain is a direct and immediate consequence of using fossil fuels as an energy source.

Electricity may look like a clean fuel source but in actual fact it is one of the dirtiest sources of energy.

Coal is burnt in the power stations and produces carbon dioxide and sulfur dioxide. Brown coal is a younger fuel then black coal and contains much less sulfur content. Brown coal from the LaTrobe Valley (Victoria Australia) has only 0.3%, by mass, sulfur.

Carbon dioxide reacts with water to form carbonic acid according to the equation below. Carbonic acid is a very weak acid.

CO2(g) + H2O(l) => H2CO3(aq)

Sulfur dioxide, produced by burning coal, reacts with oxygen and water vapour to form sulfuric acid according to the equations below.

2SO2(g) + O2(g) => 2SO3(g)

 Sulfur trioxide reacts with atmospheric water to produce sulfuric acid.

SO3(g) + H2O(l) => H2SO4(aq)
Oxides of nitrogen occur naturally through lightning, bacterial action and volcanic activity. Oxides of nitrogen have increased significantly through human activity. When oxygen and nitrogen are mixed in high temperature, internal combustion engines nitrogen(II) oxide (NO) is formed, according to equation (1) on the right. When NO is released into the atmosphere it reacts with oxygen to form nitrogen(IV) oxide (NO2), according to equation (2). When combined with water in the atmosphere a mixture of nitrous and nitric acids is formed according to equation (3).

1) N2(g) + O2(g) => 2NO(g)

2) 2NO(g) + O2(g) => 2NO2(g)

3) 2NO2(g) + H2O(l) => HNO3(aq) + HNO2(aq)
As these acids are formed in atmospheric water the rain that falls is known as acid rain. The pH of acid rain is about 5.5 or less. Acid rain has caused the destruction of vast forests and is responsible for the devastation of fish populations in rivers and lakes.
Continue with carbon dioxide in the sea.