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问题 选择题

一定温度下，将a mol气体A充入到恒温恒容容器中，发生如下反应．A（g）

2B（g）+C（g）达平衡后再加入a mol A气体，达到新平衡后，与原平衡相比较，错误的是（　　）

A．A的转化率减小

B．B和C的比值不变

C．B的质量分数增大

D．平均相对分子质量增大

答案

反应物只有一种，达平衡后再加入a mol A气体，相当于在原平衡的基础上缩小体积，则压强增大，平衡向逆反应方向移动，则

A．平衡向逆反应方向移动，A的转化率减小，故A正确；

B．B和C按化学计量数之比反应，二者的比值不变，故B正确；

C．平衡向逆反应方向移动，B的质量减小，质量分数减小，故C错误；

D．平衡向逆反应方向移动，气体的总物质的量减小，质量不变，则平均相对分子质量增大，故D正确．

故选C．

单项选择题

温室外气温超过（）时，单纯的自然通风或强制通风满足不了温室生产的要求。

A.15℃

B.20℃

C.30℃

D.35℃
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单项选择题

When anyone opens a current account at a bank, he is lending the bank money. He may (1) the repayment of the money at any time, either (2) cash or by drawing a check in favor of another person. (3) , the banker-customer relationship is that of debtor and creditor who is (4) depending on whether the customer’s account is (5) credit or is overdrawn. But, in (6) to that basically simple concept, the bank and its customer (7) a large number of obligations to one another. Many of these obligations can give (8) to problems and complications but a bank customer, unlike, say, a buyer of goods, cannot complain that the law is (9) against him.

The bank must (10) its customer’s instructions, and not those of anyone else. (11) , for example, a customer opens an account, he instructs the bank to debit his account only in (12) of checks drawn by himself. He gives the bank (13) of his signature, and there is a very firm rule that the bank has no right or (14) to pay out a customer’s money (15) a check on which its customer’s signature has been (16) It makes no difference that the forgery may have been a very (17) one: the bank must recognize its customer’s signature. For this reason there is no (18) to the customer in the practice, (19) by banks, of printing the customer’s name on his checks. If this (20) Forgery, it is the bank that will lose, not the customer. (254 words)

6（）

A.support

B.contrast

C.regard

D.addition
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