问题 计算题

(5分)氮氧化物(如NO2、NO等)进入大气后,不仅会形成硝酸型酸雨,还可能形成光化学烟雾。因此必须对含有氮氧化物的废气进行处理。

(1)用氢氧化钠溶液可吸收废气中的氮氧化物。反应的化学方程式:NO2+NO+2NaOH===2NaNO2+H2O,产物NaNO2中N元素的化合价为   ;已知“HNO2”读作“亚硝酸”,则NaNO2的名称为    

(2)氨气(NH3)也可用来处理氮氧化物。例如,氨气与二氧化氮反应:8NH3+6NO2===7N2+12H2O。若某工厂排出废气中NO2含量为0.5%(体积分数),则处理1.0×1033这种废气,需要多少千克氨气(假设此时NO2气体的密度为2.0千克/米3,计算结果保留2位小数)? (计算过程填写在答题纸上)

答案

(1)+3 亚硝酸钠  (2)4.93kg

(1)根据化合物的化合价为0进行计算,(2)先算出NO2的质量,根据化学方程式列比例式进行解答

(2)(写出完整的计算过程)

解:M=ρV=2.0千克/米3×1×1033×0.5%=1×104克=l0千克

设氨气的质量为x

8NH3 + 6NO2 ===7N2 + 12H20   

136  276

x    10kg

136︰276=x︰10kg

x=4.93 kg

答:氨气的质量为4.93千克.

阅读理解与欣赏
阅读理解

During adolescence(青春期), peers(同龄人) play a large part in a young person's life and typically replace family as the center of a teen's social activities. Some kids give in to peer pressure because they want to be liked or because they worry that other kids may make fun of them if they don't go along with the group. Others may go along because they are curious to try something new that others are doing. The idea that "everyone's doing it" may influence some kids to leave their better judgment, or their common sense, behind. 

As children grow, develop, and move into early adolescence, contacts with one's peers and the attraction of peer identification (认同)increases. As pre-adolescents begin rapid physical, emotional and social changes, they begin to question adult standards and the need for parental guidance. They find it good to turn for advice to friends who understand— friends who are in the same position themselves. By trying new things and testing their ideas with their peers, there is less fear of being laughed at.

There are two levels of peer pressure. The first is in the large group: for most teens a school or a youth group are examples. This is the situation that gets the most attention. The second is in the close relationship with one or several best friends. This is the situation that is sometimes disregarded. The large group puts a general pressure on its members. It sets the standard for clothing, music, entertainment, and "political correctness". The pressure can be avoided by keeping quiet or by putting on the appearance of agreement.

小题1:Why can’t some children follow their common sense?

A.Because they want to be liked by everybody.

B.Because they don’t want to make fun of others.

C.Because they are curious about their new friends.

D.Because they think all the children will do the same.小题2:When in pre-adolescence, who may children ask for suggestions?

A.Parents

B.Teachers

C.Friends

D.Classmates小题3:Which word can replace the underlined word disregarded in the last paragraph?

A.unnoticed

B.mentioned

C.disagreed

D.avoided小题4:What might be discussed in the following paragraph?

A.The reasons of peer pressure.

B.The advantages of peer pressure.

C.Peer pressure from close friends.

D.Peer pressure from a youth group.