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问题 问答题

某研究小组为比较Al和Fe的金属性强弱，设计了图1所示的装置，甲中锥形瓶内盛放的是100ml稀盐酸（反应前后溶液体积变化可以忽略不计）．

（1）若要比较产生气体的快慢有两种方法，一种是比较产生相同体积气体所需的时间，另一种是比较______．

（2）为了确保“Al和Fe的金属活动性不同是导致产生气体速率不同的唯一原因”，实验时需要控制好反应条件．实验时除需保证甲中液体的体积、物质的量浓度和温度相同外，还需保证______．

（3）实验测得产生气体的速率（v）与时间（t）的关系如图2所示，则t1～t2时间内速率逐渐加快说明该反应是______（填放热或吸热）反应，t2～t3时间内速率逐渐减慢的主要原因是______．

（4）能使甲中的反应停止的操作是______．

答案

（1）由v=

△V
△t
知，反应速率与气体的体积和时间有关，所以一种是固定体积比较时间，另一种是固定时间比较体积．

故答案为：相同时间内产生气体体积大小；

（2）影响化学反应速率的因素有反应物的浓度、溶液的温度、固体的表面积等，所以还需保证Al和Fe表面积相同．

故答案为：Al和Fe表面积相同；

（3）该反应是一个放热的反应，随着反应的进行，放出的热量越多，溶液的温度越高，温度越高反应速率越大；随着反应的进行，溶液中盐酸的浓度不断减小，浓度越小反应速率越小．

故答案为：放热；盐酸浓度不断减小；

（4）要想使反应停止，没有反应物即可，所以将铁丝或铝丝从溶液中拔出即可停止反应．

故答案为：铁丝或铝丝从溶液中拔出．

单项选择题


Directions: There are 4 passages in this part. Each of the passages is followed by 5 questions or unfinished statements. For each of them there are 4 choices marked A, B, C and D.
Passage One

On cold days in Delhi, the poor light bonfires (篝火) of tyres, trees and rags whose fumes mix with the exhaust from the city’s 2 million vehicles to form a thick smog. On most days in Mexico City, a blanket of pollution cuts off views of the surrounding mountains. On one famous occasion it got so bad that birds fell dead out of the sky on to the Zocalo, the city’s main square. Throughout the developing world, smogs in many big cities are getting worse as more people use cars and more manufacturing firms are belching out (喷出) pollution. Congestion is on the rise, too: according to one estimate, a car in Bangkok now spends the equivalent of 40 days a year stuck in traffic. The air in Asia’s cities, like the water in its rivers, is particularly unhealthy, containing levels of dust and smoke several times higher than in the rich countries’ cities.
Environmentalists in the developed world also worry about air pollution in poorer countries, not just out of the goodness of their hearts but because they fear it may affect their own backyard. Carbon-dioxide emissions, thought to be the cause of global warming, are growing particularly fast in developing countries. So are emissions of sulphur dioxide, blamed for acid rain, which sometimes falls hundreds of miles from the source of the pollution.
But the harm that air pollution causes in the developing countries themselves is much more serious and immediate. The biggest concern are indoor air pollution, lead emissions and small particles. Indoor pollution in poor countries is not much talked about, but it is often as damaging to health as smoking cigarettes. Around a third of all energy consumed in developing countries comes from wood, crop residues and dung, which are often burnt in poorly designed stoves within ill-ventilated (通风很差的) huts. Studies of women in India and Nepal exposed to smoke from such fuels show that their death rates from chronic respiratory disease are similar to those of heavy smokers.
Lead has long been known to be dangerous in large doses. But only since the 1970s have scientists been aware that relatively small quantities of lead in the bloodstream can be harmful to humans. In particular, "many studies show a correlation between levels of lead in children’s blood and lower IQ scores, hearing loss and hyperactivity (活动过度).
But the kind of air pollution thought to cause the most damage to human health in developing countries is that from small particles. Caused by vehicle exhausts, coal-burning smoke from factories and dust stirred up by vehicles, these particles easily find their way into people’s lungs. Studies the world over have shown a p positive correlation between small particles in the air and death rates.

The kind of air pollution that is most harmful to health is caused by ______.

A．lead emissions

B．carbon-dioxide emissions

C．sulphur dioxide emissions

D．small particles
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多项选择题

现代激励理论中的主要代表理论有（）。

A．管理过程理论

B．公平理论

C．社会合作理论

D．三重需要理论

E．目标设置理论
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