问题 多选题

低温脱硝技术可用于处理废气中的氮氧化物,发生的化学反应为:2NH3(g)+NO(g)+NO2(g)

180℃
催化剂
 2N2(g)+3H2O(g)△H<0在恒容的密闭容器中,下列有关说法正确的是(  )

A.平衡时,其他条件不变,升高温度可使该反应的平衡常数增大

B.平衡时,其他条件不变,增加NH3的浓度,废气中氮氧化物的转化率增大

C.单位时间内消耗NO和N2的物质的量比为1:2时,反应达到平衡

D.其他条件不变,使用高效催化剂,废气中氮氧化物的转化率增大

答案

A、正反应为放热反应,升高温度,平衡向逆反应方向移动,平衡常数减小,故A错误;

B、增大一个反应物浓度,其它反应物转化率增大,故B正确;

C、单位时间内消耗NO和N2的物质的量比为1:2时,等于化学计量数之比,反应到达平衡,故C正确.

D、使用催化剂平衡不移动,废气中氮氧化物的转化率不变,故D错误.

故选BC.

阅读理解

C

Of all the things we eat and drink, water is the most important. Not all people realize this, but it is quite true. The human body can live without food for a long time, but two or three days without water usually result in death.

Many people do not understand how much water the human body needs, but many people do not drink enough, especially in the hot weather. Most people drink when they are thirsty but often need more water after exercises.

65 to 70 percent of the human body is water. Water is important in several different ways. Most people need five to seven litres of water every day, but we need not drink this amount because a lot comes from the food we have. If we don’t have enough water, however, we will feel tired and many become ill. Do you know what the best drink is? Yes, you are right. Cold water!

64.Do most people drink five litres of water every day?

A. Yes, because water is the most important

B. No, because what we eat contains water

C. Yes, because we can’t live without water

D. No, because we are not thirsty

65.How much water are there in the human body?

A. About three fourths of the human body is water.

B. Nearly a half of the human body is water.

C. Less than a half of the human body is water.

D. Almost one fourth of the human body is water.

66.When do we need more water?

A. In cold weather or after exercises.

B. In hot weather or after exercises.

C. Before breakfast, lunch and supper.

D. When we feel tired or become ill.

67.Which of the following is not right?

A. Cold water is the best drink.

B. Few people understand how much water the human body needs.

C. Not all the people realize water is the most important.

D. When we feel tired or become ill, we never need any water.

单项选择题