问题 问答题

书写下列反应的文字表达式,并指出反应类型.

(1)水通电分解____________反应

(2)氢气燃烧____________反应

书写反应中涉及的化学式

______.

______.

答案

(1)水在通电条件下反应生成氢气和氧气.

该反应的文字表达式为:水

通电
氢气+氧气.

该反应由一种物质反应生成两种物质,符合分解反应的概念,属于分解反应.

该反应的化学方程式为:2H2O

 通电 
.
 
2H2↑+O2↑.

(2)氢气与氧气在点燃条件下反应生成水.

该反应的文字表达式为:氢气+氧气

 点燃 
.
 
水.

该反应由两种物质反应生成一种物质,符合化合反应的概念,属于化合反应.

该反应的化学方程式为:2H2+O2

 点燃 
.
 
2H2O.

故答案为:

(1)水

通电
氢气+氧气;分解;2H2O
 通电 
.
 
2H2↑+O2↑.

(2)氢气+氧气

 点燃 
.
 
水;化合;2H2+O2
 点燃 
.
 
2H2O.

阅读理解

Packaging is an important form of advertising.A package can sometimes motivate someone to buy a product.For example, a small child might ask for a breakfast food that comes in a box with a picture of a TV character.The child is more interested in the picture than in breakfast food.Pictures for children to color or cut out, games printed on a package, or a small gift inside a box also motivate many children to buy products or to ask their parents to buy for them.

Some packages suggest that a buyer will get something for nothing.Food products sold in reusable containers are examples of this.Although a similar product in a plain container might cost less, people often prefer to buy the product in a reusable glass or dish, because they believe the container is free.However, the cost of the container is added to the cost of the product.The size of a package also motivates a buyer.Maybe the package had “Economy Size” or “Family Size” printed on it.This suggests that the larger size has the most product for the least money.But that is not always true.To find it out, a buyer has to know how the product is sold and the price of the basic unit.

The information on the package should provide some answers.But the important thing for any buyer to remember is that a package is often an advertisement.The words and pictures do not tell the whole story.Only the product inside can do that.

小题1:From the passage we know the buyer pays more attention to __________.

A.the size of a container

B.a container with attractive picture

C.a well-designed container

D.a plain container with low cost小题2:What suggestion does the author give in the passage?

A.It’s not good to buy the product which is sold in a glass or dish.

B.The quality of a container has nothing to do with the quality of the product.

C.The best choice for a buyer is to buy a product in a plain package.

D.A buyer should buy what he needs most rather than a well-designed package.小题3:What is the best title for the passage?

A.How to Package a Product.

B.How to Make an Advertisement.

C.How to Sell Product.

D.How to Treat the Package Wisely.

问答题 简答题