问题 填空题

(1)用化学用语表示下列物质:1个氢分子______,2个氢原子______,钾离子______,硫酸根离子______,氢氧化镁______,天然气的主要成分______.

(2)26.4g的(NH42SO4中含N元素的质量是______g.

(3)写出下列反应的电离方程式或化学方程式:

①氯化钙在溶液中电离出钙离子和氯离子______;

②实验室用双氧水制取氧气______.

答案

(1)一般在微粒的前面加化学计量数表示微粒的个数,

氢气是双原子分子,氢的元素符号是H,故答案为:H2

氢的元素符号是H,元素前面加化学计量数表示原子的个数,故答案为:2H 

钾离子带一个单位正电荷,故答案为:K+

硫酸根离子带两个单位的负电荷,故答案为:SO42-

化学式的书写和读法刚好相反,故答案为:Mg(OH)2

天然气的主要成分是甲烷,故答案为:CH4

(2)氮元素的质量为:26.4×

28
132
×100%=5.6克,故答案为:5.6克,

(3)①氯化钙中钙显+2价,氯显-1价,根据电荷代数和为零的原则,故答案为:CaCl2═Ca2++2Cl-

②双氧水在二氧化锰的催化下生成水和氧气,故答案为:2H2O2

 MnO2 
.
 
2H2O+O2↑,

阅读理解

If you often feel tired and the doctor can’t find anything wrong with you, you may be in a state of subhealth(亚健康). Subhealth is a state between health and illness. Most of the subhealthy people are middle-aged ones who are usually stressed out because of work and family. And some of them are students who are having exams.

If you are subhealthy, it is not difficult for you to become well soon. You should have good living habits. For example, you should get up early and go to bed early. And you should exercise regularly(有规律地). Exercising can keep you healthy. As for meals, it is better to eat less salt and sugar. Vegetables, fruit and fish are important to your body. You should eat more of them. It is not good to eat too much at one meal, because it may cause unhealthy changes in the digestive tract(消化道). And at last, a balanced diet is very helpful in staying away from(远离)subhealth.

小题1:How may you feel if you’re subhealthy?

A.Happy

B.Comfortable

C.Tired

D.Sad小题2:According to the passage, who will probably(可能地) be subhealthy?

A.Teachers and students

B.Parents and children

C.Middle-aged people and students

D.The young and the old小题3:What should you do if you are subhealthy?

A.Relax and have good living habits

B.Go to see the doctor and ask for some medicine.

C.Go to hospital in foreign countries.

D.Stay at home and not talk to others小题4:If you want to have good living habits,      .

A.you need to get up early and go to bed early.

B.you should exercise very often

C.you should eat less salt and sugar and eat more vegetables, fruit and fish

D.All above(上边的)小题5:What is the main(主要的) idea of the passage(短文)?

A. What is subhealth.

B. How to keep away from subhealth.

C How to keep subhealthy.

D. Why are you subhealthy?

单项选择题 A1/A2型题