搜题请搜索小程序“爱下问搜题”
问题 问答题

邻苯二甲酸二酯是一种塑化剂，化学式为C24H38O4．

（1）邻苯二甲酸二酯中碳、氢、氧三种元素的质量比是______；

（2）邻苯二甲酸二酯中碳元素的质量分数计算式为______．

答案

（1）邻苯二甲酸二酯中碳、氢、氧三种元素的质量比=（12×24）：（1×38）：（16×4）=144：19：32；

（2）邻苯二甲酸二酯中碳元素的质量分数=

12×24
12×24+1×38+16×4
× 100%．

故答案为：（1）144：19：32；（2）

12×24
12×24+1×38+16×4
× 100%．

阅读理解

Mr Smith gave his wife money every Friday evening. His wife always spent it all the next Wednesday, so that for the next three days she had no money to spend at all. One day Mr Smith asked her," But how did you spend all that money?" She answered, "I don't know . "So one Friday evening, Mr Smith gave her money together with an exercise book and a pencil. He said to his wife ,"Please write down how you spend the money . "Next Tuesday, his wife had no money again. Mr Smith took the exercise book to see how she had spent it. "I have done what you told me ,"she said gladly. She had written "Friday, I got 18 pounds from Mr Smith. "on the first page, and on the second page, she wrote ,"Tuesday, I have spent it all. "

小题1:Mrs Smith always spent all the money ____.

A．the next day

B．in four days

C．in a week

D．on next Wednesday小题2:Mr Smith gave his wife an exercise book and a pencil and asked her____

A．to do homework

B．to have a look

C．to write down how she spent the money

D．to draw a picture on it小题3:Mrs Smith was ____ to do what Mr Smith asked her to .

A．happy

B．sad

C．sorry

D．excited小题4:Mr Smith gave his wife money ____ a week.

A．once

B．twice

C．three times

D．four times小题5:The story tells us that Mrs Smith was not very ____.

A．glad

B．tall

C．careful

D．Good
查看答案
单项选择题

经纬仪由照准部、( )和基座三部分组成。

A．垂直度盘

B．望远镜

C．支架

D．水平度盘
查看答案