问题 填空题

已知该反应中H2O2只发生在如下过程H2O2→O2

(1)该反应中的还原剂是                 

(2)该反应中,发生还原反应的过程是                 

(3)写出该反应的化学方程式,并标出电子转移的方向和数目。

(4)如反应转移了0.3mol电子,则产生的气体在标准状况下体积为        

答案

(1)H2O2     (2)H2CrO4  Cr(OH)3

(3)2H2=2Cr(OH)3+3O2↑+2H2O

(4)3.36L

由于在反应中H2O2只发生了H2O2→O2,即H2O2只作还原剂,故只能是H2CrO4(高价铬)作氧化剂,其反应方程式为:2H2CrO4+3 H2O2=2Cr(OH)3+3O2↑+2H2O,在反应中转移6 mol e-生成3 mol O2,故转移0.3 mol e-生成O2为:0.3 mol×1/2×22.4  L· mol-1=3.36L。

阅读理解

A king in Africa had a close friend that helped him grow up. The friend had a habit of looking at everything positively(肯定)that happened in his life and saying “This is good”.

One day the king and his friend were out hunting. The friend would prepare the guns for the king. The friend did something wrong in preparing one of the guns, and after the gun from his friend, the king fired it and his thumb(拇指) was blown off. On seeing the situation the friend said as usual, “This is good!” The king replied, “No, this is not good!” He was very angry and sent his friend to jail(监狱).

About a year later, the king was hunting in a forest. Cannibals(食人者) caught him and took him to their village. As they were going to kill him, they noticed that the king was missing a thumb. They never ate anyone who was less than whole, so they sent the king back.

When he returned home, he felt sorry for his treatment of his friend. He went quickly to the jail to speak with his friend. “You were right”, he said. “It was good that thumb was blown off.” And he told the friend all that had just happened. “And so I am very sorry for sending you to jail for so long. It was bad for me to do this.”

“No,” his friend replied, “this is good!” “What do you mean? How could it be good that I sent my friend to jail for a year?” 

“If I had not been in jail, I would have been with you, and I would have been eaten!”

小题1:From the story we learn that ________.

A.the king was not a good friend indeed

B.the king’s friend always knew what would happen

C.the friend would say “This is Good !” when anything happened

D.the king was not good at hunting at all.小题2:The king was sent back by Cannibals because _______.

A.Cannibals never ate a king

B.the king’s friend was in jail

C.the king had a gun with him

D.the king missed his thumb小题3:The best title for the reading is _______.

A.The Lucky King

B.The Great Friend

C.Nothing Stops Real Friendship

D.Everything Happens for the Good

选择题