搜题请搜索小程序“爱下问搜题”
问题 选择题

在标准状况下，称量一个充满氯气的容器质量为74.6克，若改充氮气，其质量为66克，则容器的容积为（　　）

A．11.2L

B．5.6L

C．4.48L

D．2.24L

答案

假设气体的物质的量为nmol，容器的质量为mg，则：

mg+nmol×71g/mol=74.6g

mg+nmol×28g/mol=66g

联立方程，解得n=0.2mol

气体的体积为V=0.2mol×22.4L/mol=4.48L．

所以容器的容积为4.48L．

故选C．

阅读理解

In many English homes people eat four meals a day. They have breakfast at any time from seven to nine in the morning. They eat porridge(粥) eggs or bread and drink tea or coffee at breakfast. Lunch comes at one o’clock. Afternoon tea is from four to five in the afternoon and dinner is about half past seven. First they have soup, then they have meat or fish with vegetables. After they eat some other things, like bananas, apples or oranges. But not all English people eat like that. Some of them have their dinner in the middle of the day. Their meals are breakfast, dinner, tea and supper and all these meals are very simple.

小题1:Many English people have ______ meals a day.

A. two           B. three         C. four  

小题2:People may have _______ for their breakfast according to the passage.

A. tea and eggs    B. hamburgers and tea    C. coffee and salad 

小题3:People have lunch at _______.

A. any time     B. one     C. five   

小题4:People don’t have _______ for their dinner.

A. bananas and apples   B. porridge  C. meat and fish 

小题5:Most Englishmen have dinner ________.

A. in the evening      B. at any time    C. at noon 
查看答案
多项选择题 X型题

独活的功效是（）

A.清湿热

B.祛风湿

C.化湿

D.解表

E.止痛
查看答案