Experimental conclusion of studying air composition

The experimental conclusion of studying air composition is that there are at least two gases in the air, one supporting combustion and the other not.

Experiments to study air composition: experimental materials: candles, glass sheets, water tanks, gas containers, clean water, etc. Experimental method: (1) Stick a candle on the glass and put it at the bottom of the sink; (2) adding clear water that does not flow through the candle into the water tank and lighting the candle; (3) Cover the candle with a container.

Experimental phenomenon: the candle goes out quickly, and the water level in the gas container rises after the candle goes out. It is concluded that there are at least two gases in the air, one supporting combustion and the other not. ?

Air is a mixture of many gases. Its constant components are oxygen, nitrogen, argon, neon, helium, krypton, xenon and other rare gases, and its variable components are carbon dioxide and water vapor, and their contents in the air will change slightly in a very limited range with different locations and temperatures on the earth.

As for the uncertain components in the air, they vary from region to region. For example, places near metallurgical plants will contain sulfur dioxide, and places near chlor-alkali plants will contain chlorine gas. In addition, there are traces of hydrogen, ozone, nitrous oxide, methane and more or less dust in the air.