问题 填空题

实验室用如图装置制取氢气,并进行氢气在氯气(Cl2)中燃烧的实验.纯净的H2可以在黄绿色的Cl2中安静燃烧,发出苍白色火焰,生成氯化氢(HCl)气体.请回答下列问题.

(1)写出图中有标号仪器的名称:

a______;b______.

(2)在点燃氢气之前,要先检验______.

(3)写出氢气点燃后在氯气中燃烧的文字表达式:______.该反应的基本类型属于______.

答案

(1)根据仪器用途写出仪器名称,a 试管;b 集气瓶

(2)氢气具有可燃性,点燃不纯的氢气可能会发生爆炸,因此点燃之前要验纯

(3)氢气在氯气中燃烧生成氯化氢,化学方程式为:H2+Cl2

 点燃 
.
 
2HCl,该反应反应物是两种,生成物是一种,是化合反应;

故答案为:(1)a 试管;b 集气瓶.

(2)氢气的纯度.

(3)H2+Cl2

 点燃 
.
 
2HCl. 化合反应

填空题
阅读理解

People diet to look more attractive. Fish diet to avoid being beaten up, thrown out of their social group, and getting eaten as a result. That is the fascinating conclusion of the latest research into fish behavior by a team of Australian scientists.

The research team have discovered that subordinate fish voluntarily diet to avoid challenging their larger competitors. “In studying gobies we noticed that only the largest two individuals, a male and female, had breeding (繁殖) rights within the group,” explains Marian Wong. “All other group members are nonbreeding females, each being 5-10% smaller than its next largest competitor. We wanted to find out how they maintain this precise size separation.”

The reason for the size difference was easy to see. Once a subordinate fish grows to within 5-10% of the size of its larger competitor, it causes a fight which usually ends in the smaller goby being driven away from the group. More often than not, the evicted fish is then eaten up.

It appeared that the smaller fish were keeping themselves small in order to avoid challenging the boss fish. Whether they did so voluntarily, by restraining how much they ate, was not clear. The research team decided to do an experiment. They tried to fatten up some of the subordinate gobies to see what happened. To their surprise, the gobies simply refused the extra food they were offered, clearly preferring to remain small and avoid fights, over having a feast.

The discovery challenges the traditional scientific view of how boss individuals keep their position in a group. Previously it was thought that large individuals simply used their weight and size to threaten their subordinates and take more of the food for themselves, so keeping their competitors small.

While the habits of gobies may seem a little mysterious, Dr. Wong explains that understanding the relationships between boss and subordinate animals is important to understanding how hierarchical (等级的) societies remain stable.

The research has proved the fact that voluntary dieting is a habit far from exclusive to humans. “As yet, we lack a complete understanding of how widespread the voluntary reduction of food intake is in nature,” the researchers comment. “Data on human dieting suggests that, while humans generally diet to improve health or increase attractiveness, rarely does it improve long-term health and males regularly prefer females that are fatter than the females’ own ideal.”

小题1:When a goby grows to within 5-10% of the size of its larger competitor, it        .

A.faces danger

B.has breeding rights

C.eats its competitor

D.leaves the group itself小题2:The underlined words “the evicted fish” in Paragraph 3 refer to        .

A.the fish beaten up

B.the fish found out

C.the fish fattened up

D.the fish driven away小题3:The experiment showed that the smaller fish        .

A.fought over a feast

B.went on diet willingly

C.preferred some extra food

D.challenged the boss fish小题4:What is the text mainly about?

A.Fish dieting and human dieting.

B.Dieting and health.

C.Human dieting.

D.Fish dieting.