问题 选择题

下列实验误差分析错误的是

A.用润湿的pH试纸测稀碱溶液的pH,测定值偏小

B.用容量瓶配制溶液,定容时俯视刻度线,所配溶液浓度偏小

C.滴定前滴定管内无气泡,终点读数时有气泡,所测体积偏小

D.测定中和反应的反应热时,将碱缓慢倒入酸中,所测温度值偏小

答案

答案:B

A选项湿润的pH试纸测稀碱液的pH时,碱液被稀释,pH值偏小,正确。

B选项用容量瓶配置溶液定容时俯视刻度线,所加水偏少,所配溶液浓度偏大,错误。

C选项滴定前滴定管内无气泡,终点读数时有气泡,所测体积偏小,溶液就是读数偏小,正确。

D选项测定中和反应反的应热时,将碱缓慢倒入酸中,热量损失比较多,应该一次倒入,否则所测温度值偏小,D正确。答案选B。

听力题

完成句子

小题1:“They didn’t take measures in time”, the expert said firmly and angrily, “otherwise the explosions ________________.” (happen)

“他们没有及时采取措施,”专家坚定且愤怒地说道,“否则爆炸不会发生。”

小题2:Soon after getting off his horse, the captain appeared at the second storey windows, _______________ nothing but trees. (see)

下马不久,上尉就出现在二楼的窗口了, 从那里除了树木他什么也没看到。

小题3:Rosalyn loves sports. She is proud ________________ competitions and to have broken a record by running 800 meters this year. (participate)

罗莎琳热爱运动。她为今年参加比赛并打破800米赛跑的记录而感到骄傲。

小题4:____________________ should be no reason for treating one’s neighbors as strangers. (occupy)

工作繁忙不应该成为“对面不相识”的借口。

小题5:He went on a bus tour with a group of people, ________________ before. (travel)

他和一群人乘坐巴士旅行,这群人中的大多数以前从没旅行过。

小题6:My son has been away from home for about 2 weeks. I’m looking forward to ___________. (hear)

我儿子离家差不多两周了。我盼望着收到他的来信。

小题7:I think that only in this way ______________ the knowledge and skills needed for my job. (acquire) 我认为只有通过这种方式我才能获得工作所需要的知识与技能。

小题8: _______________ that China produces one third of the world’s cigarettes. (astonish)

令人震惊的是全世界三分之一的香烟是由中国生产的。

小题9:Even though Tony had been so clever, he would have to be rebuilt— you cannot have _________

with machines.(fall)

尽管托尼很聪明,他还得作一番改造——总不能允许女人与机器人相爱吧。

小题10:It’s time for me to quit smoking, for I do hope to live as __________________as my grandfather has. (healthy)

我该戒烟了,因为我真的希望能过着像我的祖父一样长寿健康的生活。

单项选择题