風化作用--solution 同Co2 的關係...
solution 唔係淨 係關 water 事的嗎？
點解"solution enhanced by Co2 from respiration"??
- 某人Lv 51 十年前最愛解答
空氣中o既CO2 會溶o係水, 變成Carbonic Acid
令solution o既效果加強(Acid 嘛)
Rainfall is naturally slightly acidic because atmospheric carbon dioxide dissolves in the rainwater producing weak carbonic acid. In unpolluted environments, the rainfall pH is around 5.6. Acid rain occurs when gases such as sulphur dioxide and nitrogen oxides are present in the atmosphere. These oxides react in the rainwater to produce stronger acids and can lower the pH to 4.5 or even 4.0. Sulfur dioxide, SO2, comes from volcanic eruptions or from fossil fuels, can become sulfuric acid within rainwater, which can cause solution weathering to the rocks on which it falls.
One of the most well-known solution weathering processes is carbonation, the process in which atmospheric carbon dioxide leads to solution weathering. Carbonation occurs on rocks which contain calcium carbonate such as limestone and chalk. This takes place when rain combines with carbon dioxide or an organic acid to form a weak carbonic acid which reacts with calcium carbonate (the limestone) and forms calcium bicarbonate. This process speeds up with a decrease in temperature and therefore is a large feature of glacial weathering.
The reactions as follows:
CO2 + H2O <-> H2CO3
carbon dioxide + water <-> carbonic acid
H2CO3 + CaCO3 <-> Ca(HCO3)2
carbonic acid + calcium carbonate <-> calcium bicarbonate