问题 选择题

某溶液含有①NO3-②HCO3-③SO32-④CO32-⑤SO42-等五种阴离子。向其中加入少量的Na2O2固体后,溶液中离子浓度基本保持不变的是(设溶液体积无变化) (  )

A.①

B.①②④

C.①③⑤

D.①③④⑤

答案

答案:A

题目分析:Na2O2与水反应生成氢氧化钠,溶液呈碱性,HCO3-与OH-反应生成CO32-,则HCO3-离子浓度减小,CO32-离子浓度增大;

Na2O2具有强氧化性,将SO32-氧化为SO42-,则SO32-离子浓度减小,SO42-浓度增大;

NO3-浓度基本不变.

故选A。

点评:本题考查Na2O2的性质以及离子反应,难度不大,注意Na2O2的强氧化性。

单项选择题

People from East Asia tend to have more difficulties than those from Europe in distinguishing facial expressions - and a new report published online in Current Biology explains why.

Rachael Jack, University of Glasgow researcher, said that rather than scanning evenly (均匀 的) across a face as Westerners do, Easterners fix their attention on the eyes.

"We show that Easterners and Westerners look at different face features to read facial expressions," Jack said. "Westerners look at the eyes and the mouth in equal measure, whereas Easterners favor the eyes and neglect (忽略) the mouth. "

According to Jack and her colleagues, the discovery shows that human communication of emotion is more complex than previously believed. As a result, facial expressions that had been considered universally recognizable cannot be used to reliably convey emotion in cross cultural situations.

The researchers studied cultural differences in the recognition of facial expressions by recording the eye movements of 13 Western Caucasian and 13 East Asian people while they observed pictures of expressive faces and put them into categories : happy, sad, surprised, fearful, disgusted, angry,

or neutral. They compared how accurately participants read those facial expressions using their particular eye movement strategies.

It turned out that Easterners focused much greater attention on the eyes and made significantly more errors than did Westerners. "The cultural difference in eye movements that they show is probably a reflection of cultural difference in facial expressions," Jack said. " Our data suggest that whereas Westerners use the whole face to convey emotion, Easterners use the eyes more and mouth less. "

In short, the data show that facial expressions are not universal signals of human emotion. From here on, examining how cultural factors have diversified these basic social skills will help our under- standing of human emotion. Otherwise, when it comes to communicating emotions across cultures, Easterners and Westerners will find themselves lost in translation.

What were the people asked to do in the study()

A. To make a face at each other.

B. To get their faces impressive.

C. To classify some face pictures.

D. To observe the researchers’ faces.

单项选择题 B1型题