相同质量的下列醇，分别和过量的金属钠作用放出氢气最多的是（ ）
A．甲醇
B．乙醇
C．乙二醇
D．丙三醇
答案：D
题目分析：设醇的质量为mg。经计算，A项：放出氢气是(m/32)g；B项：放出氢气是(m/46)g；C项：放出氢气是(m/31)g；D项：放出氢气是(3m/92)g。故选D。
点评：解本类型题比较简单的方法是从有机物中羟基的物质的量和产生氢气的物质的量之间的关系进行分析，根据反应实质计算如要得到等质量的氢气，需要消耗选项物质的质量即可。
Museums have changed. They are no longer places that one “should” go to but to enjoy. At a science museum in Canada, you can feel your hair stand on end as harmless electricity passes through your body. At the Children’s Museum in New York, you can play an African drum. There are no “Do Not Touch” sign in some other museums in the USA. More and more museum directors have realized that people learn best when they can become part of what they are seeing. In many science museums, the visitors are encouraged to touch, listen, operate and experiment so as to discover scientific rules for themselves. The purpose is not only to provide fun, but also help people feel at home in the world of science. If people don’t understand science, they will be afraid of it; and if they are afraid of science, they will not make the best use of it. One cause of all these changes is the increase in wealth and spare time. Another cause is that the number of young people grow in the population. Many of them are college students or college graduates. They see things in a new and different way. They want art that they can take part in. The same is true of s  cience and history.The old museums have been changing and the government is encouraging th  e building of new, modern museums. In the States and Canada, there are more than 6000 museums, twice as many as there were 25 years ago.Title: 小题1: __________________________
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