问题 问答题

如图是哈药集团制药六厂生产的“新盖中盖牌”高钙片标签上的部分文字,请仔细阅读后回答下列问题.

新盖中盖牌

[主要原料]碳酸钙、维生素D

[功效成分]补钙  每片中含:

钙(以Ca计)500mg

维生素D100  IU

[食用方法]每日一次,每次一片

[规     格]2.5g/片

(1)维生素种类较多,其中维生素D2的化学式为C28H44O,则维生素D2的相对分子质量为______;维生素D2中C、H、O三种元素的质量比为______;

(2)计算高钙片中碳酸钙的质量分数______.

答案

(1)维生素D2的相对分子质量为12×28+1×44+16=396;维生素D2中C、H、O三种元素的质量比为(12×28):(1×44):(16×1)=84:11:4.

(2)根据题意,每片“新盖中盖牌”高钙片的质量为2.5g,每片含钙500mg=0.5g,则含碳酸钙的质量为0.5g÷

40
40+12+16×3
×100%=1.25g,高钙片中碳酸钙的质量分数为
1.25g
2.5g
×
100%=50%.

故答案为:(1)396;84:11:4;(2)50%.

实验题
单项选择题

A

Ask Dr Jeffers.

This month Dr. Jeffers is answering questions about human brain and how it works. Dear Dr. Jeffers,

One of my colleagues, Felix Moeller, told me that scientists are learning to use computer to ’read minds’. Is there any truth to this story

--Jane Leon, New York, USA

Dear Ms. Leon,

Well, a lot of research is being conducted in this area, but so far, the brain scanning equipment and corresponding computer programs haven’ t been able to actually read thoughts. In one experiment, test subjects(受试者) were connected to scanning equipment and shown two numbers on a screen. They were then asked to choose between adding or subtracting(减)the two numbers. Using this method, researchers were able to follow brain processes and make the correct assumptions (假 设) 70 percent of the time. It’ s not quite mind reading, but it’ s certainly a first step.

--Dr. J.

Dear Dr. Jeffers,

My three-year-old son loves it when I dig my fingers into his sides and tickle (胳肢)him until he laughs uncontrollably. The other day I noticed him trying to tickle himself but he couldn’t do it. Why not

--Glenn Lewis, Vancouver, Canada

Dear Mr. Lewis,

It’s because of how the brain works. The brain is trained to know what to pay attention to and what to ignore. It causes us to ignore physical feelings we expect to happen, but it causes a mild panic reaction when there is an unexpected feeling. For example, you don’ t notice how your shoulder feels while you’ re walking down the street. But if someone comes up behind you and touches you lightly on the shoulder, you may jump in fear. It’ s that unexpected part that causes the tickle reaction.

--Dr. J.

People laugh when tickled by others because the feeling is().

A. unexpected

B. expected

C. comfortable

D. uncomfortable