问题 问答题

将下列化学术语的序号填在后面的横线上(用序号填空):

①吸附②蒸发③过滤④乳化

(1)由饱和的食盐水得到食盐晶体______;(2)除去食盐中的泥沙,先溶解,再______;

(3)洗洁精洗去碗筷上的油污______;(4)活性炭除去冰箱中的异味______.

答案

解;(1)蒸发结晶适用于溶解度随温度变化不大的可溶性物质,氯化钠的溶解度受温度的影响变化不大,由饱和的食盐水得到食盐晶体可用蒸发结晶的方法.

(2)过滤是把不溶于液体的固体与液体分离的一种方法,食盐易溶于水,泥沙难溶于水,除去食盐中的泥沙,先溶解,再过滤.

(3)洗洁精是洗涤剂,有乳化作用,能将大的油滴分散成细小的油滴随水冲洗,可用于洗去碗筷上的油污.

(4)活性炭具有吸附性,能吸附异味和色素,可除去冰箱中的异味.

故答案为:(1)②;(2)③;(3)④;(4)①.

选择题
单项选择题

Questions 51-55 are based on the following passage.


To Err is Human


by Lewis Thomas
Everyone must have had at least one personal experience with a computer error by this time. Bank balances are suddenly reported to have jumped from $ 379 into the millions, appeals for charitable contributions are mailed over and over to people with crazy sounding names at your address, department stores send the wrong bills, utility companies write that they’re turning everything off, that sort of thing. If you manage to get in touch with someone and complain, you then get instantaneously typed, guilty letters from the same computer, saying, "Our computer was in error, and an adjustment is being made in your account."
These are supposed to be the sheerest, blindest accidents. Mistakes are not believed to be the normal behavior of a good machine. If things go wrong, it must be a personal, human error, the result of fingering, tampering a button getting stuck, someone hitting the wrong key. The computer, at its normal best, is infallible.
I wonder whether this can be true. After all, the whole point of computers is that they represent an extension of the human brain, vastly improved upon but nonetheless human, superhuman maybe. A good computer can think clearly and quickly enough to beat you at chess, and some of them have even been programmed to write obscure verse. They can do anything we can do, and more besides.
It is not yet known whether a computer has its own consciousness, and it would be hard to find out about this. When you walk into one of those great halls now built for the huge machines, and standing listening, it is easy to imagine that the faint, distant noises are the sound of thinking, and the turning of the spools gives them the look of wild creatures rolling their eyes in the effort to concentrate, choking with information. But real thinking, and dreaming, are other matters. On the other hand, the evidence of something like an unconscious, equivalent to ours, are all around, in every mail. As extensions of the human brain, they have been constructed the same property of error, spontaneous, uncontrolled, and rich in possibilities.

The author uses his hypothesis that "computers represents an extension of the human brain" in order to indicate that ______.

A. human beings are not infallible, nor are computers
B. computers are bound to make as many errors as human beings
C. errors made by computers can be avoided the same as human mistakes can be avoided
D. computers axe made by human beings and so are their errors