题目

在一定质量的氯酸钾中加入少量的二氧化锰并加热到不再产生气体为止，下图中能正确表示反应前后各物质的质量变化（m）与时间（t）关系的是（    ）         答案：B A: Summer holiday is coming.   1 ? B: Yes, I’m going to my hometown. A:   2 ? B: For about a month.   3 ? A: I want to travel to Hainan Island. It’s a beautiful place of interest. B:   4 . But I have to visit my grandparents in my hometown. A: It doesn’t matter. If you stay in your hometown for fewer days, you’ll have enough time to go traveling. B:   5 . Then I will go to my hometown as soon as the holiday begins. A: OK! I will wait for you until you come back. B: That’s a deal! Thank you. 1.                                  2.                                  3.                                  4.                                  5.