搜题请搜索小程序“爱下问搜题”
问题 选择题

在反应方程式2A+B=C+3D中，已知50gA与12gB恰好完全反应可生成30gC物质，若D物质的相对分子质量为32，则A的相对分子质量为（　　）

A．25

B．50

C．75

D．100

答案

设D的质量为X，根据质量守恒，列等式：50g+12g=30g+X，解得X=32g；

设A的相对原子质量为Y，

2A+B=C+3D

50g    32g

2Y     3×32

可得比例式：

50g
32g
=
2Y
3×32
，解得Y=75．

故选C

改错题

假如英语课上老师要求你修改你同桌写的一篇作文，文中共有10处语言错误，请在错误的地方增加、删除或修改某个单词。

增加：在缺词处加一个漏字符号（^），并在其下面写出该加的词。

删除：把多余的词用斜线（\）划掉。

修改：在错的词下面划一横线，并在该词下面写出改正后的词。

注意：

1．每处错误及其修改均仅限一词；

2．只允许修改10处，多者（从第11处起）不计分。

Dear editor,

Next year I'll go to university and becoming a college student, and I have never been away from my parents．I don't know what to face my university life．I hear many new students are at a loss when we are at university．They can't take care of themselves in everyday life, and often feel lonely and homesick．Clothes, money or mobile phone are sometimes gone．And because different weather and food, they often get ill．Some even rent rooms outside the campus, which I don't think it is so safely． Could you tell me how to deal with these problems so that I would be able to get used the university life in the future．
查看答案
填空题

羌活胜湿汤的功用是（）。
查看答案