问题 选择题

下列物质中,属于共价化合物的是

A.NH4Cl

B.H2SO4

C.NaCl

D.I2

答案

答案:B

共价化合物只含有共价键,大都有不同的非金属元素组成,个别如AlCl3也为共价化合物,但由非金属性元素组成的化合物不一定为共价化合物,也可能为离子化合物,如铵盐.

解答:解:A.NH4Cl为离子化合物,不是共价化合物,故A错误;

B.H2SO4为共价化合物,只含有共价键,故B正确;

C.NaCl为离子化合物,故C错误;

D.I2为单质,不是化合物,故D错误.

故选B.

阅读理解

阅读理解。

     Do you know Eskimos? Let me tell you something about their lives.

     Eskimos live near the North Pole (北极). There are only two seasons there, winter and summer.

     There is no spring or autumn there. The winter nights are long. You can't see the sun for more than

two months, even at midday. The summer days are long. For more than two months, the sun never goes

down and there's no night.

     Eskimos have warm clothes. They make their clothes from the skins of animals. From skins (皮毛)

they make coats, caps and shoes.

      Near the North Pole trees can't grow, for it is too cold there. The Eskimos have to make their houses

from skins, snow or stone. When they got out in storms and can't get back home, they make houses of snow.

They leave these houses when the storm is over.

     Life is hard for the Eskimos, but they still like to live there.

1.Near the North Pole there are _____ in a year. [ ]

A. two seasons - winter and summer

B. two seasons - spring and autumn

C. four seasons

D. two seasons sometimes and four seasons sometimes

2.How long does the longest day or night last (持续) near the North Pole? [ ]

A. 24 hours

B. Over a week

C. A month

D. Over two months

3.Eskimos use skins to make _____. [ ]

A. clothes

B. houses

C. trees

D. both A and B

4.There are no _____ near the North Pole. [ ]

A. days

B. nights

C. trees

D. animals

5.Eskimos make houses of snow to protect (保护) themselves from _____. [ ]

A. animals

B. storms

C. snow

D. rain

单项选择题