问题 选择题

在一密闭容器内有氧气,二氧化碳,水蒸气和一种未知物质M,在一定条件下充分反应,测知反应前后各物质的质量如下:

物质氧气二氧化碳M
反应前质量/g1322232
反应后质量/g49074X
下列说法正确的是(  )

A.X应为64

B.M中一定不含氧元素

C.该反应是分解反应

D.M的化学式为C2H5OH

答案

氧气反应后少了128g说明反应了128g,二氧化碳多了88g说明生成了88g二氧化碳,水蒸气多了72g说明生成了72g水,根据质量守恒定律,M属于反应物,并且反应了32g,所以X值为0,算出二氧化碳中碳元素的质量为24g,水中氢元素的质量为8g,又因为二氧化碳中碳元素的质量、水中氢元素的质量都是由M中出来的,而24g+8g=32g所以M中无氧元素.所以只有B是正确的.

故选B

阅读理解

阅温度理解。

     A Father’s day is a day set aside for honouring fathers in church services and in the home. It’s

celebrated in the U.S. in the third Sunday of June. This idea was begun by Mrs John Bruces Dodd,

who in 1909 persuaded an organization in Washington to

     salute fathers with special church services. The idea was officially agreed to by President Woodrow

Wilson in 1916. In 1924, President Calvin Coolidge suggested national celebration of the day to

form closer relations between fathers and their children, and to impress upon fathers the full measure

of their duties. The red or white rose is recognized as the official Father’s Day flower.

1. Father’s Day, at first, meant ______.

A. to honor fathers in church services and in the home

B. to win honor for fathers in church services

C. to do honour to fathers at home

D. to warn the fathers of their duties

2. Father’s Day was first celebrated by _____.

A. the French      

B. the British      

C. the German      

D. the American

3. The first president who agreed to Father’s Day was _____.

A. Woodrow Wilson

B. Calvin Coolidge

C. George Washington

D. Abraham Lincoln

4. The president wanted Father’s Day to be a day on which _____.

A. people remembered their fathers

B. the relations between fathers and their children became closer

C. fathers must remember that they should be good fathers

D. both B and C

5. According to the passage, this idea was begun by______.

A. Woodrow Wilson    

B. Calvin Coolidge

C. George Washington    

D. Mrs. John Bruces Dodd

单项选择题