(2013?Yueyang second model) Water is the source of life, through the study of chemistry, we further recognize the important role of water. (1) Please write the composition of elements and water

(1) the composition of elements and water is the same substance is hydrogen peroxide, chemical formula: H2O2;

(2) water pollutants in the nitrogen and phosphorus content is too high, here "nitrogen and phosphorus" refers to the elements;

(3) the tap water is not pure water, if you want to make pure water, should be taken to purify the method is distillation; Detergent has an emulsifying function, can wash the oil on the dishes;

(4) by the figure 1 can be seen, the solution of substance A can no longer dissolve substance A, so it is a saturated solution, shown in figure 2, 20 ℃, solubility curve b is located below the solubility curve a, indicating that at this time, a is greater than the solubility b; figure 1 shows that the substance B is dissolved all the time and the substance A has a solid material remaining, indicating that at this time, B The solubility of the substance is greater than the substance a; Therefore, Figure 2, a indicates that the solubility curve of the substance a; the solubility of the substance a with the increase in temperature and increase, in order to make the remaining a solid in the test tube to continue to dissolve the method can be used is to increase the temperature, will be 10 ℃ when the a saturated solution is warmed to 20 ℃ (solvent does not evaporate), a solubility with the increase in temperature and increase the solubility of the bottom of the undissolved a dissolved to make the solute The mass of the solution increases, so the mass fraction of solute becomes larger.

The answer is: (1) H2O2; (2) A; (3) distillation, emulsification; (4) A, a, increase the temperature, become larger.