问题 选择题

NA表示阿伏加德罗常数,以下说法正确的是(    )[

A.56g金属铁由原子变为离子时失去的电子数为NA

B.在通常条件下,1mol氩气含有的原子数为2NA

C.在标准状况下,2.24 L氨气所含的电子总数约为NA

D.含有NA个原子的镁在足量的二氧化碳气体中充分燃烧生成固体的质量为40g

答案

答案:C

A 错误,56g金属铁由原子变为离子时失去的电子数为3NA或者2NA

B.错误,在通常条件下,1mol氩气含有的原子数为NA

C 正确,在标准状况下,2.24 L氨气为0.1mol,所含的电子总数约为NA

D 错误,镁在足量的二氧化碳气体中充分燃烧生成氧化镁和碳,固体质量大于40g。

选择题
单项选择题

D

To err is human. To blame the other guy is even more human.

Common sense is not all that common.

Why tell the truth when you can come up with a good excuse

These three popular misquotes(戏谑的引语) are meant to be jokes, and yet they tell us a lot a-bout human nature. To err, or to make mistakes, is indeed a part of being human, but it seems that most people don’t want to accept the responsibility for the problem. Perhaps it is the natural thing to do. The original quote about human nature went like this: "To err is human, to forgive, divine (神圣的)."This saying mirrors an deal: people should be forgiving of others’ mistakes. Instead, we tend to do the opposite—find someone else to pass the blame on to. However, taking responsibility" for something that went wrong is a making of great maturity.

Common sense is what we call clear thought. Having common sense means having a good general plan that will make things work well, and it also means staying with the plan. Common sense tells you that you take an umbrella out into a rainstorm, but you leave the umbrella home when you hear a weather forecast for sunshine. Common sense does not seem to be common for large organizations, because there are so many things going on that one person cannot be in charge of everything. People say that in a large company," the right hand does not know what the left hand is doing. "

And what is wrong with a society that thinks that making up a good excuse is like creating a work of art One of the common problems with making excuses is that people, especially young people, get the idea that it’s okay not to be totally honest all the time. There is a corollary(直接推论) to that: if good excuse is "good" even if it isn’t honest, then where is the place of the truth

What is the author’s opinion about a good excuse()

A.Making a good excuse is sometimes a better policy.

B.Inventing a good excuse needs creative ideas.

C.A good excuse is as rewarding as honesty.

D.Bitter truth is better than a good excuse.