有下列物质：①氢氧化钠固体　②铜丝　③氯化氢气体　④稀硫酸　_爱下问搜题

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问题填空题

有下列物质：①氢氧化钠固体　②铜丝　③氯化氢气体　④稀硫酸　⑤二氧化碳气体　⑥熔融氯化钠　⑦碳酸钠粉末　⑧蔗糖晶体．请用序号填空：

（1）上述状态下可导电的是______．（2）属于电解质的是______．

（3）属于非电解质的是______．

（4）上述状态下的电解质不能导电的是______．

答案

（1）能导电的物质--必须具有能自由移动的带电的微粒，金属铜中存在能自由移动的带负电的电子能导电，稀硫酸和熔融氯化钠中都有能自由移动的正负离子，也能导电，故答案为：②④⑥；

（2）电解质是在水溶液中或熔融状态下能够导电的化合物，故答案为：①⑥⑦；

（3）非电解质是在水溶液中或熔融状态下都不能能够导电的化合物，故答案为：③⑤⑧；

（4）题目中的电解质只有氢氧化钠固体、熔融氯化钠、碳酸钠粉末，氢氧化钠和碳酸钠在水溶液中或熔融状态下才能够导电，固体状态下没有能自由移动的正负离子，不能导电，故答案为：①⑦．

完形填空

A young man and an old man were waiting for a bus at a station. They sat _1__ each other. “What’s that in your bag?” asked the young man, pointing to a big bag beside the ___2__.
“Money, nothing but money,” answered the old man. The young man could ___3___ believe his own ears. “What?” he said to himself in surprise. “So much money? My God! How I __4__ to be able to get so much money!” Then he began to think about how to get the money.
The old man ___5__ tired and it seemed that he could hardly keep his eyes open. “Are you tired, sir?” asked the young man. “Then you’d better lie down on the ___6____ and have a good rest. Don’t worry about ___7___. I’ll wake you up in time. ”
“All right . It’s very kind of you, young man. ” The old man lay down and ___8___ he fell asleep.
The young man took the big bag gently. ___9___ when he was just going to run away , he found a corner of his fur coat (皮衣) was ___10___ the old man’s body . Several times he tried to pull it out, but he couldn’t. At last he took off his ____11____ and went away with the bag.
The young man ran out of the station as quickly as his ___12___ could carry him, he reached a place, and there he thought the old man couldn’t ___13___ him, he stopped and quickly opened the bag.
To his surprise, there was ___14___ but old newspapers in it. He hurried to the station at once. But when he got there, he found the old man was ___15____

判断题

用绝缘滑车法更换绝缘子，只适用于在LGJ400型以下的导线上作业