问题
选择题
向一定量的饱和石灰水中加入少量生石灰，y随时间的变化趋势如图所示，则y可表示
溶质的质量 溶剂的质量
溶液的质量 ④溶液中溶质的质量分数
A．
B．④
C．
D．④
答案
答案：A
题目分析：生石灰与水反应放热，使水的质量减少，生成的氢氧化钙要结晶析出，溶液的质量也要随温度的改变发生变化，因为温度不变的质量分数不变，故答案选择A
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向一定量的饱和石灰水中加入少量生石灰，y随时间的变化趋势如图所示，则y可表示
溶质的质量 溶剂的质量
溶液的质量 ④溶液中溶质的质量分数
A．
B．④
C．
D．④
答案：A
题目分析：生石灰与水反应放热，使水的质量减少，生成的氢氧化钙要结晶析出，溶液的质量也要随温度的改变发生变化，因为温度不变的质量分数不变，故答案选择A
| 阅读理解。 | ||||||||||
At this moment in different places of the world people are doing different things.
| ||||||||||
| 1. According to the passage we can see that at night some people in Moscow like to _____. | ||||||||||
| A. go to watch a ballet B. do shopping C. wait for buses D. go to the library | ||||||||||
| 2. When children in Los Angeles are starting their lessons, people in Beijing are _____. | ||||||||||
| A. playing basketball B. seeing films C. having lessons D. sleeping | ||||||||||
| 3. From the passage, we can see the time in New York now is _____. | ||||||||||
| A. 6∶00 B. 9∶00 C. 10∶00 D. 12∶00 | ||||||||||
| 4. We know that London is 3 hours _____. | ||||||||||
| A. earlier than Moscow B. later than Moscow C. earlier than Los Angeles D. later than Los Angeles | ||||||||||
| 5. This passage mainly talks about _____. | ||||||||||
| A. science B. holidays C. time difference D. life in western countries |
