Chemical problems (related to the solubility of substances)

① Take a certain volume and measure the weight. The volume is equal to the weight of distilled water (the volume is in milliliters and the weight is in grams). (2) when cold water is heated, bubbles often appear in the water. Because the temperature rises, the solubility of gas decreases and the gas escapes. Therefore, when the weather is sultry, the oxygen content in the fish pond decreases, and fish can breathe more oxygen when swimming near the water surface.