问题 选择题

设NA为何伏加德罗常数的数值,下列说法不正确的是(  )

A.常温常压下,2gD2O中含有的电子总数为NA

B.标况下22.4LCl2通入足量H2O中充分反应,转移电子数为NA

C.常温常压下,46gNO2和N2O4混合气体中含有的原子数为3NA

D.1molK与足量O2反应,生成K2O、K2O2和KO2的混合物时转移的电子数为NA

答案

A、2gD2O物质的量=

2g
20g/mol
=0.1mol;含有的电子总数为NA,故A正确;

B、标况下22.4LCl2物质的量为1mol,与H2O中充分反应,存在化学平衡,转移电子数小于NA,故B错误;

C、NO2和N2O4最简比相同为NO2,所以只需要计算46gNO2中的原子数,物质的量为1mol,含原子数为3NA,故C正确;

D、钾元素原子全部反应,电子转移根据1molK失去电子数计算,1molK与足量O2反应,生成K2O、K2O2和KO2的混合物时转移的电子数为NA,故D正确;

故选B.

单项选择题
阅读理解

阅读理解。

     BAGHDAD-An Iraqi soldier went on the rampage at a joint security station in northern Iraq on Wednesday,

shooting dead two US soldiers and wounding six, the US military said. 

                                         

     A US soldier looks at destroyed vehicles at a parking lot after a bomb attack in Baghdad November 12,2008.

A parked car bomb killed four people and wounded 14 others, including two policemen, in Sadoun street in

central Baghdad, police said. [Agencies]

     The US military said the soldier opened fire on the Americans at the station. one of many in which Iraqi and

US troops operate side by side, in the city of Mosul. "The soldiers were in the courtyard……an Iraqi soldier

entered and shot two soldiers, killing one, mortally wounding another,and then spraying the others," said US

army spokeswoman for northern Iraq Major Peggy Kageleiry.

     "He was engaged by counter-fire and killed," she added. A local morgue said it had received the body of the

Iraqi soldier, riddled with bullets.

     Two local police sources and an Iraqi army source, all of whom declined to be named because of the

sensitivity of the subject, said a quarrel had broken out between the Iraqi and US soldiers at the joint station.

     But Kageleiry denied there was any altercation between the soldiers before the shooting.

     "The US soldiers had no conversation with this soldier and there was no interaction of any kind before they

were murdered," she said.

1. What does the word "altercation" mean?

A. disagreement

B. conflict

C. quarrel

D. debate

2. Why didn't the local police sources tell their name?

A. Because they were afraid of American soldiers.

B. Because American soldiers quarreled with them.

C. Because the government asked them not to do so.

D. Because they didn't want to be involved in it.

3. What can we infer from the passage?

A. There was only one conflict between the two armies.

B. More people will die.

C. The quarrel caused the shooting.

D. Kageleiry was sure that American soldiers did nothing wrong.