问题 选择题

物质的用途与性质密切相关,下列说法错误的是(  )

A.氮气常用作保护气,是由于氮气的化学性质不活泼

B.铁制栏杆表面常涂“银粉漆”(铝粉)防生锈,是由于铝的化学性质比铁稳定

C.洗涤剂常用来洗涤油污,是因为洗涤剂有乳化功能

D.CO、H2常用来冶炼金属,是因为它们都具有还原性

答案

A、氮气常用作保护气,是由于氮气的化学性质不活泼,正确.

B、铁制栏杆表面常涂“银粉漆”(铝粉)防生锈是因为铝和氧气反应生成了致密而坚硬的氧化物薄膜,阻止了铝和氧气的进一步反应.不正确.

C、洗洁精能将油污乳化为液体小珠滴,易于洗涤餐具上的油污,正确;

D、CO、H2常用来冶炼金属,是因为它们都具有还原性,正确;

故选B

连线题
阅读理解

阅读短文,在改写后的短文空白初填入一个适当的词,使其完整通顺。

     Most American businesses are open five days a week. American school children go to school five days

a week, too. American families usually have a two-day weekend. The weekend is Saturday and Sunday.

Over the weekend, people spend their time in many ways. Many families enjoy weekend together. They may

go shopping, go for a drive, or visit friends. They may also invite friends over and have a party at home. Many

families take part in sport during the weekend. Running, hiking, playing volleyball and swimming are popular

in summer. Skiing and skating are the favorite winter sports. Weekends are also a time for American families

to work on something in their yards or in the house. Many families plant flowers and have vegetable gardens.

Some families spend the weekends to paint or repair their houses. For most Americans, weekend are very busy.

     Most Americans    1    five days a week and they have a two-day    2   The people of many families spend

their time in different    3  . They may go out to see their friends or   4    friends to come to have a party at

home. Over the weekend, many people are interested in    5   , some of them like to go   6    in summer and 

  7    in winter. Some families   8    with their flowers and    9   in their gardens. The others are busy   10  

 or repairing their houses at the weekends.

1._____ 2._____ 3._____ 4._____ 5._____ 6._____ 7._____ 8._____ 9._____ 10._____