题目

Has anyone ever told you that eating carrots will help you see in the dark?This is just one of many incorrect beliefs you may have heard. Below, TEENS has picked out scientific explanations for three mistakes that people make about their eyes. Let’s take a look.Can eating carrots improve your eyesight?Carrots are rich in vitamin A, which helps the eyes to turn light into information for your brain. This allows people to see in darker places.However, eating more carrots won’t help you see better. A certain minimum amount will help, but a large number of carrots will not give you superhuman 甲、乙、丙三种固体物质的溶解度曲线如图所示，请回答：（1）25℃时，将25g甲固体加入到50g水中，充分溶解并恢复到原温度后，得到溶液的质量为 g。（2）要使35℃时接近饱和的甲溶液变成该温度下的饱和溶液，可采用的一种方法是 。（3）现有操作步骤： a．溶解 b．过滤 c．降温结晶 d．加热浓缩；若甲固体中含有少量乙，则提纯甲的操作步骤是 (填字母序号)。（4）将35℃时丙的饱和溶液降温到25℃，则其溶液的溶质质量分数 （填“变大”、“变小”或“不变”）。（5）向100g35℃的水中加入45g甲固体，发现全部溶解，一段时间后又有部分甲的晶体析出。你认为“全部溶解”的原因可能是 。