右图是甲、乙、丙三种固体物质的溶解度曲线．请回答：
（1）随着温度的升高溶解度减小的物质是______；
（2）50℃时，要完全溶解20g乙物质得到饱和溶液，需要水______g；
（3）30℃时，将等质量甲、乙、丙三种物质分别加到等质量的水中，充分溶解后只得到一种饱和溶液，该饱和溶液中的溶质是______．
（1）根据溶解度曲线可以得出丙物质的溶解度随温度的升高而降低；
（2）在50℃时，乙物质的溶解度为40g，即在该温度下100g水中溶解40g乙即达到饱和，所以在该温度下要溶解20g乙物质并得到饱和溶液需要50g水；
（3）30℃时，丙的溶解度最小，根据题意将等质量甲、乙、丙三种物质分别加到等质量的水中，充分溶解后只得到一种饱和溶液，所以可以知道溶解度最小的丙物质达到饱和状态．
故答案为：（1）丙；
（2）50；
（3）丙．
The Peppered Moth, a kind of insect, is found in England. It is light brown in color and likes to settle on trees which are also light brown. This makes the moth difficult to be seen and birds are less likely to notice and eat it. But with the development of industry, smoke from factories began to reach the trees where the moth settled. It made the trees blacker. Then something very strange took place: in industrial areas, the Peppered Moth began to change color. It became darker as well. Although the change took several years, some scientists soon noticed that newly-born moths were a little darker than usual. A scientist called Kettle Well decided to make a careful study of this. He marked some of the light moths and some of the darker ones, and set them free in the woods near Birmingham, an industrial city. Later he retarget as many the marked moths as possible ( The result was given in the chart ). Kettle Well’s research was done in the early 1950s. Soon afterwards Britain introduced new laws to reduce smoke and factory pollution. Can you imagine what would happen to the Peppered Moth as the air became cleaner again?
A. the Peppered Moth changed its color B. the Peppered Moth couldn’t be easily found on them C. industry in England developed quickly D. the smoke from factories polluted them 2. The Peppered Moth began to change its color in industrial areas because _____________________________. A. it changed its color all the time B. it was fond of the color of its living place C. it had to protect itself by doing so D. it was a special sort of insect 3. From the results of Kettle Well’s research, we can see that _________________. A. many more of the light moths were killed or eaten B. more than one-fifth of the light moths escaped being killed C. three times as many dark moths were kept safe as light ones D. more dark moths were killed in industrial areas 4. Kettle Well’s work gives us a good example of _________________________. A. Air Pollution B. Choice of Color C. Laws of Nature D. Changing Insects 5. As the air became cleaner, _________________________. A. the number of the light moths increased B. the total number of the light moths remained unchanged C. more of the darker moths would be recaught D. the darker moths changed into the light ones before long |