Marsh gas thus requires for its complete combustion double its volume of oxygen. Therefore, by exploding 100 volumes of marsh gas with 400 of oxygen, there will remain in the jar a bulk of 300 volumes of gas. It will consist of 100 volumes of carbonic dioxide, the result of the combustion, and the 200 volumes of free oxygen which was left uncombined, the steam having been condensed to water. 405. If two volumes of marsh gas, weighing 16 grams, be burnt in excess of air, how many volumes of carbonic dioxide (carbonic acid) are produced? Also, what is the weight of the other compound formed at the same time? June 1876. The reaction is represented by the following equa From the inspection of the equation it may be gathered that 2 volumes of carbonic dioxide are produced. The other compound formed is 4 volumes of steam. If 2 volumes of marsh gas should weigh 16 grammes, then 2 volumes of steam will weigh 18 grammes, and therefore 4 volumes of steam weigh 36 grammes. 406. Explain the meaning of the following equation: CH1 + 202 = CO2 + 2H2O June 1873. This means that light carburetted hydrogen combines with twice its volume of oxygen to form carbonic dioxide and vapour of water. This reaction often takes place, with great loss of life, in coal mines, where the gas has been imprisoned for thousands of years. The miners call it fire-damp. By the application of a light it takes fire, and a fearful explosion ensues. But, unfortunately, the survivors of this first calamity are then subject to perhaps a more fatal one-that is, to the deadly effects of carbonic dioxide, which is the result of the combination of the light carburetted hydrogen with oxygen. In the language of miners the carbonic dioxide is called after damp, or choke damp. |