问题 计算题

小军从家中拿来一瓶久置的医用过氧化氢溶液,和同学们一起测定.他们从瓶中取出该溶液共51g,加入适量二氧化锰,生成氧气的质量与反应时间的关系如图所示:则该溶液中所含双氧水的实际质量是多少克?

答案

解:由图象可知生成氧气的质量为0.48g

设51g过氧化氢溶液中含过氧化氢的质量为x.

2H2O22H2O+O2

     68                         32

      x                       0.48 g

,x==1.02g

答:该溶液中所含双氧水的实际质量为1.02 g

改错题

短文改错

     Today is Sunday. The sky is full of sunshine, so does my life.                                    1._________

At about 9:00 am, I go to the bookstore with my friends,                                              2._________

there was a lot of new books, but I didn't know which one to buy,                                3._________

because these books were all useful to me. At last, I chose two.                                   

At 10:00 am, we went to the cinema, the film calling Titanic was very                            4. _________

popular. It took us about 3 hours to see. Having seen the film,                                      5. __________

and  everyone was deeply moved. Some friends even burst                                          6. __________

out tears. From the story, I understand that love is noble and valuable.                          7. __________     

That's a real wonderful film. It is very worth seeing again.                                              8. __________

                                                                                                                                   9. __________

What a happy day! I hope tomorrow I will be even happy!                                          10. _________

问答题