题干

下列有关化学反应速率的说法正确的是 

A:用铁片和稀硫酸反应制取氢气时,改用98%的浓硫酸可以加快产生氢气的速率

B:100mL2mol/L的盐酸跟锌片反应,加入适量的氯化钠溶液,反应速率不变

C:升高体系的温度,活化分子的百分数增大,反应速率加快

D:在密闭容器中进行 N2 (g)+ O2(g) 2NO(g)的可逆反应,若温度不变压强不变,充入氦气则该反应的速率加快

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C

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    Here comes a story that many years ago a man arrived at a village in India to catch monkeys so he could sell them to zoos. The monkeys, however, were very clever and every sort of trap he set failed. A young boy watched the man's pathetic efforts and laughed.

    The man said, “If you can catch me a monkey, I'll give you $ 2.” That was a huge amount of money then.

    The boy went to his home and took a clay pot with a narrow neck. He placed a few nuts around the pot and put lots of nuts inside. He then tied the pot to a tree and told the man, “We should have a rest in a few hours. Let's wait in the village. The monkey will call us when he is ready.”

    Certainly enough, a band of monkeys soon discovered the nuts and the pot. One slipped his hand in the pot and grabbed a handful of nuts, but he couldn't pull his hand out of the narrow opening of the pot because his fist(拳头) was clenched. The monkey feared and started making loud noises. Some of the other monkeys tried unsuccessfully to pull the pot off his hand.

    The boy and the man heard the noises and the boy got a big strong bag. As they approached the monkeys they all ran away except the one with its hand in the pot. The boy grabbed the monkey and the pot. The man was amazed and asked the boy the secret of his monkey trap, “Why was it so easy for the monkey to get his hand in but so hard to get it out?”

    The boy laughed and said, “The monkey could have easily got his hand back out and escaped, but he would have had to let go of the nuts in the pot and he just wasn't willing to let go. They never are.”

    What lessons can be learned from this story? Do people sometimes trap themselves by holding onto things that they should let go? Do you?

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