问题
选择题
用NA表示阿伏加德罗常数的值，下列叙述中错误的是
A．标准状况下，22．4L CH4与18g H2O所含有的电子数均为10NA
B．室温下，21.0g乙烯和丁烯的混合气体含有的碳原子数目为1.5NA
C．等物质的量的甲基(－CH3)与羟基(－OH) 所含电子数相等
D．1mol乙烷含有的共价键数目为8NA
答案
答案：D
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用NA表示阿伏加德罗常数的值，下列叙述中错误的是
A．标准状况下，22．4L CH4与18g H2O所含有的电子数均为10NA
B．室温下，21.0g乙烯和丁烯的混合气体含有的碳原子数目为1.5NA
C．等物质的量的甲基(－CH3)与羟基(－OH) 所含电子数相等
D．1mol乙烷含有的共价键数目为8NA
答案：D
I like winter best. it is very cold ,it is good for skating. I often go skating on Sundays my friends. When it snows , everything turns white. Trees and house are with thick snow. How beautiful the world !My friends and I like to make snowmen. Sometimes we make snowballs and them to each other. That’s a very interesting game. In winter we have a holiday, and the Spring Festival is in winter,too.
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