请简单讨论表面活性剂在稀溶液中对表面张力的影响情况。_爱下问搜题

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问题问答题简答题

请简单讨论表面活性剂在稀溶液中对表面张力的影响情况。

答案

参考答案：

在稀溶液中，表面活性剂按极性相似规则绨合分子、溶液中的表面活性剂单个分子和吸附层中表面活性剂分子三者之间的动态平衡，表面活性剂分子不能产铺于液面，而是倾斜于液面，因此对表面张力的影响相对减小。

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完形填空阅读短文，从每题所给选项中选出可以填入空白处的最佳选项（共15分；每空1分，满分15分）
When I was young，my father told me that little acts of kindness may give one great happiness. Since then I have always tried to help people in      .
One hot summer afternoon, I was               down the highway to New York when another car suddenly      into my lane(车道). My car was in the far right lane，so it ran onto the roadside. As a(n)      driver，I moved my car quickly and skillfully back onto the highway without causing any accident. I was      with that driver，but I thought that he just did not pay attention to（注意） the lane change, and he     did not do that on purpose(故意).The car ran away     after cutting me off. Very soon it disappeared from sight. After a while，I came around a curve(弯道) and found the    car. The driver was walking along the roadside. He was an elderly man and looked     . As there was no telephone nearby and the nearest services were twenty miles away, I decided to        and see what the problem was.
The man’s car had a flat tire(瘪胎). Although he had another tire，he had nothing to work with. I decided to     him. I changed the tire for him and allowed him to sit in my air-conditioned car while I did it. Fifteen minutes later，I      the work. I was hot and tired，but I really felt     after an act of kindness to the man who had earlier    my car run off the road.
You can really enjoy great   from kindness acts, so always lend your hands to others in trouble.

B．experienced

配伍题

初生时（）
生后3~5个月时（）

A.卡介苗

B.乙型脑炎疫苗

C.麻疹疫苗

D.脊髓灰质炎疫苗

E.百日咳-白喉-破伤风混合疫苗