搜题请搜索小程序“爱下问搜题”
问题 问答题

将足量铁投入到200mLH2SO4和CuSO4的混和溶液中，充分反应后，产生H21.12L（标准状况），铁块的质量减轻了1.2g．求原溶液中c（H2SO4）及c（CuSO4）．（假设反应前后溶液的体积不变）

答案

Fe+H2SO4=FeSO4 +H2↑

     56g  1mol    22.4L

 m1（Fe） n（H2SO4） 1.12L

m1（Fe）=

56g×1.12L
22.4L
=2.8g

n（H2SO4）=

1mol×1.12L
2.24L
=0.05mol

V（液）=V（H2SO4）=V（CuSO4）=200mL=0.2L

c（H2SO4）=

n(H2SO4)
V(H2SO4)
=
0.05mol
0.2L
=0.25mol/L

     Fe+CuSO4=FeSO4+Cu

    56g  1mol      64g

m2（Fe） n（CuSO4）  m（Cu）

m（Cu）=

64g
56g
×m2(Fe)=
8
7
m2(Fe)

由题意得：m1（Fe）+m2（Fe）-m（Cu）=1.2g

2.8g+m2（Fe）-

8
7
m2(Fe)=1.2g

m2（Fe）=11.2g

n（CuSO4）=

1mol×m2(Fe)
56g
=
1mol×11.2g
56g
=0.2mol

c（CuSO4）=

n(CuSO4)
V(CuSO4)
=
0.2mol
0.2L
=1mol/L

答：原溶液中c（H2SO4）=0.25mol/L，c（CuSO4）=1mol/L．

阅读理解
阅读理解。
Sandy,
      I'm going to have a Christmas party next weekend. Are you coming? (298-3227)
                                                                                                                 Grace
Sandy,
     One of your students called. I told him to call again.
                                                                                                                  Sue
Sandy,
     The Fugitive is on now at Present Theater. Do you want to see it?
                                                                                                                 Chris
Sandy,
Mr Brown said your car was OK. You can go and get it from 9:00 am to 5:00 pm. 
                                                                                                                  Steve
Sandy,
     I found a new kind of dog food. My Sash just loves it. Would you get some for
your Lucky?
                                                                                                                  Lucy
1. When is Grace going to have a party?
A. This weekend.
B. This Friday.
C. Next weekend.
D. Next month.
2. What is "The Fugitive"?
A. A book.
B. A movie.
C. A song.
D. A ball game.
3. Maybe Lucky is Sandy's ________.
A. son
B. student
C. friend
D. dog
4. What did Mr Brown do for Sandy?
A. He fixed (修理) her car.
B. He wanted to buy her car.
C. He found a new kind of dog food.
D. He wanted her to call him at 298-3227.
5. Sandy is probably ________.
A. a doctor for animals
B. a film star
C. a teacher
D. a bus driver
查看答案
填空题

不重合的两个平面α和β．在α内取5个点，在β内取4个点，利用这9个点最多可以确定三棱锥的个数为______个．
查看答案