问题 选择题

下列离子方程式的书写与所给条件相符的是

A.将4 molCl2通入到含有4 mol FeBr2的溶液中:2Cl2+2Fe2++2Br= 4Cl+Br2+2Fe3+

B.已知亚硫酸(H2SO3)的第二级电离常数K2比偏铝酸(HAlO2)的电离常数K要大,则将少量的SO2气体通入到偏铝酸钠溶液中发生的离子反应是:AlO2+ SO2+2 H2O =Al(OH)3↓+HSO3

C.稀氨水溶液吸收了少量二氧化碳气体: NH3 ·H2O + CO2 = NH4+ + HCO3

D.在明矾溶液中加入氢氧化钡溶液至沉淀质量达到最大时发生的离子反应是: 2Al3+ +3SO42+3Ba2++6OH= 3BaSO4↓+2 Al(OH)3

答案

答案:A

题目分析:A.根据电子守恒,将4 molCl2共得到8mol电子,先和二价铁离子反应,4 mol Fe2+得到4mol电子,还有4molBr-得到电子生成了2molBr2分子,FeBr2的溶液中:2Cl2+2Fe2++2Br= 4Cl+Br2+2Fe3+,故正确;B.亚硫酸(H2SO3)的二级电离常数K2比偏铝酸(HAlO2)要大,说明酸性:亚硫酸氢根离子>偏铝酸,则亚硫酸氢根离子也能和偏铝酸钠溶液,所以将少量的SO2气体通入到偏铝酸钠溶液中发生的反应为2AlO2-+SO2+3H2O=2Al(OH)3↓+SO32-,不符合强酸制弱酸的原则,故B错误。C.稀氨水溶液吸收了少量二氧化碳气体应该生成碳酸铵,错误;D.在明矾溶液中加入氢氧化钡溶液至沉淀质量达到最大时只要保证两个物质的量之比是2:3时可达到沉淀量最大,即发生的离子反应是: 3Ba2+ + 3SO42- +2Al3+ + 6OH- ="==2" Al(OH)3↓+3BaSO4

完形填空
根据短文内容,从下框的A—F选项中选出能概括每一段主题的最佳选项。选项中有一项为多余选项。
A、One Important Factor in Conversation
B、It’s not Difficult to Talk Well.
C、A Famous Master of the Art
D、Pronunciation and Usage
E、What Makes a Good Talker
F、Talk with Strangers
小题1:_________________
The ancient Greeks were very good at making conversations, and the greatest talker of them all was philosopher Socrates. His pupil, Plato, recorded some of his supposed conversations, and we read them in ‘The dialogues’ of Plato. In many classrooms today, Socrates’ method of teaching is used.
小题2:_________________
The best talkers appear to have a great interest in and love for their fellow creatures; a curiosity about the world in general; some powers of observation and reflection; respect for their own opinions and tolerance for those of others; and quick thinking. And they talked for the fun of it, not to show off their knowledge.
小题3:_________________
A good voice must have the help of good speech, whose two assistants are clear enunciation(清晰发音)and correct pronunciation. Poor enunciation may suggest to your listeners that you lack consideration, and that you are not especially concerned about their opinion of you.
小题4:________________
Pronunciation is settled by common agreement of the community or group speaking the particular language or dialect. For standard pronunciation of words, a dictionary is your best friend. The usage of words is somewhat the same as pronunciation. To be accurate in your use of words is very important in your conversation. Dictionaries usually provide the usage of words. So whenever you meet with new words, it is a good idea to look them up in the dictionary.
小题5:_________________
Think of meeting a stranger as a chance to have a good time to talk, to make a friend. Look with a smile directly into the other’s eyes when you are introduced, and shake hands with a firm, friendly clasp. This will give you confidence. Then try to have a smooth and pleasant conversation with him.
单项选择题