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问题 问答题

如图I是实验室“制取氢气并还原氧化铜实验”的简易装置，其中铜制燃烧匙可以在试管M中上下移动，虚线框中的装置需从图Ⅱ中选取．图Ⅱ中的细铜丝一端绕成螺旋状，先在酒精灯火焰上加热，变黑后再迅速地伸到制得的氢气中．请回答下列问题：

（1）在图I中，试管M内的液体应选用______，该反

应的化学方程式为______．

（2）在图I的虚线框中，应选用图Ⅱ中的______填

“A”或“B”）装置，该装置中发生反应的化学方程

式为______．

（3）上述制氢气的方法与锌粒直接加入试管中相比，其主要优点是______．

答案

（1）氢气的实验室制法中，最好的药品选择就是锌粒与稀硫酸，因为反应速率适中易于控制，而且不会影响氢气的纯度；（2）因为氢气的密度比空气小，所以选B装置才能收集氢气并且完成氢气与氧化铜的反应；

（3）根据题目信息燃烧匙可以在试管M中上下移动，当燃烧匙脱离稀硫酸的液面时，反应物分离，反应停止．需要反应进行时可再将燃烧匙插入液面以下．

故答案是：

（1）稀硫酸Zn+H2SO4=ZnSO4+H2↑

（2）B，H2+CuO

△
.
Cu+H2O

（3）可以使反应随时发生或停止

问答题 简答题

什么是脱氧，什么是合金化？
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单项选择题

There are two factors which determine an individual’s intelligence. The first is the sort of brain he is born with. Human brains differ considerably, some being more capable than others. But no matter how good a brain he has to begin with, an individual will have a low order of intelligence unless he has opportunities to learn. So the second factor is what happens to the individual—the sort of environment in which he is reared. If an individual is handicapped environmentally, it is likely that his brain will fail to develop and he will never attain the level of intelligence of which he is capable.

The importance of environment in determining an individual’s intelligence can be demonstrated by the case of the identical twins, Peter and Mark Being identical, the twins had identical brains at birth, and their growth processes were the same. When the twins were three months old, their parents died, and they were placed in separate foster homes. Peter was reared by parents of low intelligence in an isolated community with poor educational opportunities. Mark was reared in the home of well to do parents who had been to college. He was read to as a child, sent to good schools, and given every opportunity to be stimulated intellectually. This environmental difference continued until the twins were in their late teens, when they were given tests to measure their intelligence. Mark’s IQ was 125, twenty five points higher than the average and fully forty points higher than his identical brother. Given equal opportunities, the twins, having identical brains, would have tested at roughly the same level.

This selection can best be titled（）

A．Measuring Your Intelligence.

B．Intelligence and Environment.

C．The Case of Peter and Mark.

D．How the Brain Influences Intelligence.
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