问题 选择题

为探究原电池的形成条件和反应原理,某同学设计了如下实验并记录了现象:①向一定浓度的稀硫酸中插入锌片,看到有气泡生成;②向上述稀硫酸中插入铜片,没有看到有气泡生成;③将锌片与铜片上端接触并捏住,一起插入稀硫酸中,看到铜片上有气泡生成,且生成气泡的速率比实验①中快;④在锌片和铜片中间接上电流计,再将锌片和铜片插入稀硫酸中,发现电流计指针偏转.下列关于以上实验设计及现象的分析,不正确的是(  )

A.实验①、②说明锌能与稀硫酸反应而铜不能

B.实验③说明发生原电池反应时会加快化学反应速率

C.实验③说明在该条件下铜可以与稀硫酸反应生成氢气

D.实验④说明该原电池中铜为正极、锌为负极

答案

①锌为活泼金属,能与硫酸发生置换反应生成氢气;

②铜为金属活动性顺序表中H以后的金属,不与稀硫酸反应;

③当锌和铜连接插入稀硫酸中,能形成原电池,锌较活泼,作原电池的负极,负极材料不断消耗,铜较不活泼,作原电池的正极,电极上有气泡产生,且原电池反应较一般的化学反应速率较大,反应的实质是氢离子在铜极上得电子被还原产生氢气;

④活泼性不同的锌、铜以及电解质溶液形成闭合回路时,形成原电池,将化学能转变为电能,电流计指针偏转.

不正确的只有③,

故选C.

阅读理解

Smart job-seekers need to rid themselves of several standard myths about interviewing before they start looking for a job. What follows is a list of some of these untruths and some tips to help you do your best at your next interview.

Myth 1: The aim of interviewing is to obtain (means “get”) a job offer.

Only half true. The real aim of an interview is to obtain the job you want. That often means rejecting job offers you don’t want! So before you please an employer, be sure you want the job.

Myth 2: Always please the interviewer

Not true. Try to please yourself. Of course, don’t be hostile—nobody wants to hire someone disagreeable. But there is plainly a muddle ground between being too ingratiating(逢迎)and being hostile.

Myth 3: Try to control the interview

Nobody “controls” an interview. When someone tries to control us, we resent(憎恨)it. When we try to control others, they resent us. Remember you can’t control what an employer thinks of you, just as he can’t control what you think of him. So he is ready to give and take when being interviewed; never control the interview.

Myth 4: Never interrupt the interviewer

Study the style of the effective conversationalists: they interrupt and are interrupted! An exciting conversation always makes us feel free—free to interrupt, to disagree, to agree enthusiastically. Just hang loose. Try being yourself for a change. Employers will either like or dislike you, but at least you’ll have made an impression. Leaving an employer indifferent(冷漠的)is the worst impression you can make.

小题1:To be your natural self in a job interview will__________.

A.make your interviewer angry

B.please your interviewer

C.leave an impression on the interviewer

D.leave the interviewer indifferent to you小题2:     For job seekers, efforts to control the interview are likely to __________.

A.affect the interviewer’s opinion of them

B.lead to the offer of a job

C.enable them to express themselves fully

D.help to create a favorable image of themselves小题3:The most important thing to keep in mind when being interviewed for a job is to _________.

A.try to obtain the job

B.reject the job first

C.qualify yourself for the job

D.see if it is a job you want小题4:The right attitude to a job interviewer is to be _________.

A.obedient

B.hostile

C.pleasing

D.agreeable小题5:     “hang loose” in last paragraph means to _________.

A.stay calm and relaxed

B.become weak and passive

C.take charge

D.sit back comfortably

单项选择题