问题 填空题

完成下列反应的文字表达式,并回答有关问题.

(1)加热铜丝,现象是______变______色,文字表达式:______,基本反应类型是______.

(2)实验室用双氧水制取氧气(二氧化锰粉末作催化剂):______,该反应是______(选填“吸热”或“放热”)反应.

(3)用澄清石灰水检验二氧化碳的反应:______.

(4)氢气在空气中燃烧:______,基本反应类型是______.

(5)镁带在空气中燃烧的反应:______,基本反应类型是______.

(6)加热碳酸氢铵______,基本反应类型是______.

答案

(1)加热红色的铜丝,铜丝与氧气反应生成黑色的氧化铜.

该反应的文字表达式为:铜+氧气

加热
氧化铜.

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.

(2)过氧化氢在二氧化锰的催化作用下反应生成水和氧气.

该反应的文字表达式为:过氧化氢

二氧化锰
水+氧气.

该反应过程中放出大量的热.

(3)二氧化碳与氢氧化钙反应生成碳酸钙沉淀和水.

该反应的文字表达式为:二氧化碳+氢氧化钙→碳酸钙+水.

(4)氢气和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.

(5)镁与氧气在点燃条件下反应生成氧化镁.

该反应的文字表达式为:镁+氧气

点燃
氧化镁.

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.

(6)碳酸氢铵在加热条件下反应生成氨气、水和二氧化碳.

该反应的文字表达式为:碳酸氢铵

加热
氨气+水+二氧化碳.

该反应由一种物质反应生成三种物质,符合分解反应的概念,属于分解反应.

故答案为:

(1)红色;黑;铜+氧气

加热
氧化铜;化合反应.

(2)过氧化氢

二氧化锰
水+氧气;放热.

(3)二氧化碳+氢氧化钙→碳酸钙+水.

(4)氢气+氧气

点燃
水;化合反应.

(5)镁+氧气

点燃
氧化镁;化合反应.

(6)碳酸氢铵

加热
氨气+水+二氧化碳;分解反应.

单项选择题
阅读理解

Every weekend, many Americans drive around looking for things to buy. They are taking part in an unusual kind of outdoor treasure hunt: the yard sale (旧货出售). In some parts of the country, such a sale might be called a garage sale or a moving sale. Whatever the name, the activity is the same. People sell things they no longer want.

The sellers put a paid announcement in a local newspaper. It tells when and where the yard sale will take place. It lists some of the things to be sold. Early in the morning, all the things to be sold are carried out of the house. Then they sit all day waiting for someone to take them home. Usually, the seller puts a price on each object at a yard sale. However, that price can almost always be negotiated (谈判).

Serious buyers also spend time getting ready for yard sales. They collect the newspaper announcements. Then they make lists of the sales they want to attend.

Most people who go to yard sales are not looking for anything special. They might buy an object simply because it costs so little. They enjoy bargaining over prices, even if they may hold their own yard sale to sell all the things they have bought.

To other people, yard sales are simply a way to have fun. In some communities, they are important social gatherings. Other people say yard sales help the environment. Old things are re-used instead of being thrown away.

In any case, yard sales are very popular in America. Hunting for unusual items is a sport for some people. For others, it is a way of life.

59 What can’t you get to know about the yard sales announced in a local newspaper?

A.When to attend the yard sale.

B. Where to attend the yard sale.

C. What is to be sold at the yard sale.

D. The prices of the things to be sold at the yard sale.

60 Before a yard sale, the sellers need to do all the following things EXCEPT ______.

A. putting a paid announcement in a local newspaper

B. bargaining over the prices with the buyers

C. putting the price of each object

D. carrying all the things to be sold out of the house early in the morning

61 Which of the following is NOT true according to the passage?

A. A yard sale can also be called a garage sale or a moving sale.

B. The sellers need to pay for putting an announcement in a local newspaper.

C. The sellers collect the newspaper announcements before the yard sales.

D. The prices for the items to be sold at a yard sale can be negotiated.

62.Which of the following statements is NOT mentioned as the reason why yard sales are very popular in America?

A. People can buy something special at yard sales.

B. People can buy something they really want.

C. People can enjoy bargaining over prices.

D. People regard yard sales as social gatherings.