题目内容
在“用油膜法估测分子大小”的实验中,按照油酸与酒精的体积比为
︰
配制油酸酒精溶液,用注射器滴取该溶液,测得
滴溶液的总体积为
,将一滴溶液滴入浅盘,稳定后将油酸膜轮廓描绘在坐标纸上,如图所示.已知坐标纸上每个小正方形的边长为
.
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250052470689681.jpg)
①求油膜面积;
②估算油酸分子的直径.
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005246959337.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005246975297.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005247006312.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005247022321.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005247053283.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250052470689681.jpg)
①求油膜面积;
②估算油酸分子的直径.
① S =31a2 ②![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250052470841435.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250052470841435.png)
试题分析:(1)估算油膜面积时以超过半格以一格计算,小于半格就舍去的原则,估算出31格,则油酸薄膜面积为
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005247115548.png)
(2)根据公式
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005247131733.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250052470841435.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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