题干

下列说法正确的是(   )

A:增大反应物浓度,可增大单位体积内活化分子的百分数,从而使有效碰撞次数增大

B:有气体参加的化学反应,若增大压强(即缩小反应容器的体积),可增加活化分子的百分数,从而使反应速率增大

C:升高温度能使化学反应速率增大,主要原因是增加了反应物分子中活化分子的百分数

D:催化剂不影响反应活化能但能增大单位体积内活化分子百分数,从而增大反应速率

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答案(点此获取答案解析)

C

同类题2

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    My husband hasn't stopped laughing about a funny thing that happened to me. It's funny now but it wasn't at the time.

    Last Friday, after doing all the family shopping in town, I wanted a rest before catching the train, so I bought a newspaper and some chocolate and went into the station coffee shop — that was a cheap self-service place with long tables to sit at. I put my heavy bag down on the floor, put the newspaper and chocolate on the table to keep a place, and went to get a cup of coffee.

    When I went back with the coffee, there was someone in the next seat. It was one of those wild-looking youngsters, with dark glasses and worn clothes, and hair colored bright red at the front. Not so unusual these days. What did surprise me was that he'd started to eat my chocolate!

    Naturally, I was annoyed. However, to avoid trouble — and really I was rather uneasy about him — I just looked down at the front page of the newspaper, tasted my coffee and took a bit of chocolate. The boy looked at me closely. Then he took a second piece of my chocolate. I could hardly believe it. Still I didn't dare to start an argument. When he took a third piece, I felt more angry than uneasy. I thought, "Well, I shall have the last piece." And I got it.

    The boy gave me a strange look, and then stood up. As he left he shouted out. "This woman's crazy!" Everyone stared. That was embarrassing enough, but it was worse when I finished my coffee and got ready to leave. My face went red — as red as his hair — when I realized I'd made a mistake. It wasn't my chocolate that he'd been taking. There was mine, unopened, just under my newspaper.