问题 计算题

在化学变化中,参加化学反应的物质总质量与生成物的总质量相等,且化学反应中各反应物与生成物之间的质量比是一定的。五中化学小组用加热氯酸钾与二氧化锰制取氧气,实验测得相关数据如下图所示:

 

(1)剩余的混合物中二氧化锰的质量为       g,二氧化锰在反应中的作用是       

(2)反应生成氧气的质量为        g。

(3)列式计算,求需要加热多少氯酸钾完全反应生成9.6 g氧气?

答案

(1)1.0,催化作用   (2)19.2 (3)24.5g

(1)二氧化锰在该反应过程中起催化作用,反应前后质量不变,故答案为1.0g,催化作用;

(2)根据质量守恒定律可知;氧气的质量=49.0g+1.0-30.8g=9.2g

(3)设加热氯酸钾的质量为x。

2KClO32KCl+3O2

245               96

X                 9.6g

245:96 = x: 9.6g   解得 x =24.5g

答:需要加热24.5g氯酸钾完全反应生成9.6 g氧气。

完形填空
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Nathan: There is a festival in June in our country, it’s Father’s Day.
    1   
Li Fei: Yes, it’s on the fifth day of the fifth lunar(阴历)month. We call it Dragon Boat Festival
Nathan:     2      
Li Fei: We make and eat zongzi and hold dragon boat races.
Nathan:     3       Why do you celebrate Dragon Boat Festival?
Li Fei: Oh, it is a story about Qu Yuan. He lived about two thousand years ago. His job was to give advice to the emperor. But he wasn’t trusted and often got punishment. So he jumped into the Miluo River and died.
Nathan:     4    Was the day that Qu Yuan died on the fifth day of the fifth lunar month in that year?
Li Fei:     5      From then on , Chinese people began to eat zongzi and have dragon boat races on that day to memorize him.
 A. What happened to him?
B. Is there a Chinese festival in June, too?
C. Thank you for telling me.
D. Yes, you are very smart.
E. It sounds very interesting.
F. What do you usually do on that day in China?
G. What a pity!
                                                                            
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