问题 计算题

下面是某学生做的一道计算题,请指出他的错误。题目:3.25gZn和足量的盐酸(HCl)反应制取H2,同时还生成ZnCl2。求可制得H2的质量是多少?

解:设可制得H2的质量为xg

Zn+HCl==ZnCl2+H2

65      1

3.25g     xg

x=211.25g

答:可制得H2211.25g。

错误:

(1)____________________________;

(2)____________________________;

(3)____________________________;

(4)____________________________。

请写出正确的解答过程。

答案

(1)设错了

(2)化学方程式未配平

(3)H2的相对分子质量错了

(4)计算结果错误

解题过程为:设可制得H2的质量为x

Zn+2HCl==ZnCl2+H2

65       2

3.25g      x

x=0.1g

改错题

第五部分:写作(共两节,满分35分)

第四节:短文改错(共10小题;每小题1分,满分10分)

此题要求改正所给短文的错误。对标有题号的每一行做出判断:如无错误,在该行右边横线上划一个勾(√);如有错误(每行只有一个错误),则按下列情况改正:该行多一词:把多余的词用斜线(\)划掉,在该行右边横线上写出该词,并也用斜线划掉。

该行缺一个词:在缺词处加一个漏字符号(∧),在该行右边横线上写出该加的词。

该行错一个词:在错的词下划一横线,在该行右边横线上写出改正后的词。

注意:原行没有错的不要改。

Dear Betty,

Yesterday my roommate invite me to celebrate Thanksgiving           90.        

Day with him in his house. I accepted his invitation, but as you know,     91.        

the social customs in my country is quite different from those here.          92.        

I am a little nervous now. I’m worried about make mistakes and                     93.        

losing faces before many people, too.                                             94.        

Should I bring a gift, such as candy or flowers? But should                 95.        

I arrive at on time or a little late? At the dinner table, how can I                 96.        

know which fork or knife to use? How can I let a family know                97.        

that I’m thankfully for their kindness?                                         98.        

I really find hard to decide, please help me.                         99.        

Yours,

Knowing Nothing

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