(1) We can smell the gas. From the microscopic point of view, it is because the molecules are constantly moving, moving into the air and entering people's nostrils, and they smell the smell. Ethethiol burns to produce sulfur dioxide, carbon dioxide and water. The chemical equation is: 2C2H5SH+9O2? Light it? .? 2SO2+4CO2+6H2O；

(2)SO2 can form acid rain when it meets rain, and in order to reduce environmental pollution, SO2 in the waste gas discharged from the factory can be absorbed by sufficient caustic soda solution or clean energy can be used.

(3) The main component of natural gas is methane, which is less dense than air and easy to gather above, so the alarm should be installed above the stove when it is used;

(4) When combustible gas is mixed with air or oxygen to a certain extent, it may explode when exposed to an open flame, so the purity of the gas should be tested before igniting or heating the combustible gas. Therefore, in order to test the purity of natural gas, after you collect a test tube of gas, the next thing you do is to ignite it with the nozzle down and close to the flame;

(5) When striking a match for ignition, people find that the flame stands upright on the table, and the flame will be extinguished slowly. If the inverted match is tilted slowly, it will burn more vigorously. Excuse me, the reason why the flame stands upright on the table, and the flame will be extinguished slowly is that: the heat on the table is transferred upwards, and the temperature cannot reach the ignition point of the match below;

(6) When the oil in the pan is found to be on fire before cooking, if you don't need to cover it with a lid and don't pour out the oil, you'd better pour in vegetables. The principle of this fire extinguishing is: lower the temperature below the ignition point.

Therefore, the answer is: (1) molecules are constantly moving; 2C2H5SH+9O2? Light it? .? 2SO2+4CO2+6H2O；

(2) acid rain; Use clean energy; The use of desulfurization coal, factory waste gas treatment before discharge, etc. (3) above; The main component of natural gas is methane, which is less dense than air.

(4) The nozzle is downward and close to the flame for ignition;

(5) The flame is transmitted upward by the upper heat, and the temperature cannot reach the ignition point of the match below, so it goes out;

(6) pour in vegetables; Reduce the temperature below the ignition point.