（21? Harbin) A classmate did an interesting experiment (the device has good air tightness). The whole experimental process is shown as follows: (1) Write out what happened in test tube A.

(1) According to the figure in the title, the reactants and products that react in test tube A can be written as the chemical equation 4P+5O2? Light it? .? 2P2O5；

(2) When the test tube is cooled to room temperature, the rubber stopper is removed from the water, and the liquid level in the test tube rises: the white phosphorus consumes oxygen to generate solids; The pressure of the gas in the test tube is reduced, which is less than the outside atmospheric pressure. < P > Therefore, it should be: (1)4P+5O2? Light it? .? 2P2O5；

(2) The combustion of white phosphorus consumes oxygen and generates solids; The gas pressure in the test tube decreases, which is less than the external atmospheric pressure.