题干

加热条件下,在一个密闭的容器内有如下反应,反应过程中两次测得各物质的质量如下表所示,下列说法正确的是(    )

物质

P

Q

R

W

第一次测得的质量/g

40

4

3.6

4.8

第二次测得的质量/g

待测

13

12.6

10.8

A:上述化学反应方程式一定为Q+R+W P

B:该反应R与W的质量变化之比为2:3

C:两次测定之间生成W的质量为10.8g

D:第二次测得P的质量为16g

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答案(点此获取答案解析)

D

同类题5

阅读下面短文,从短文后各题所给的A、B、C和D四个选项中,故答案选出可以填入空白处的最佳选项。

    Easter is a holiday celebrated all over the world. A lot of people like to do 1 things during the Easter weekend. One year my friends Katherine and David decided to 2 on the weekend. They lived in Houston and I lived in San Antonio, about 250km away.

    I was very 3 to go to the wedding. I 4 a new black suit, new black shoes, and a great wedding gift for Katherine and David. After having breakfast in my apartment, I was ready to go and got into my car. I started the car and was 5! The car made a very loud scratchy 6. It didn't start. My car was 7!

    I 8 called my other friends who were going to the wedding. They were all in Houston already. I was so 9. I really wanted to go to the wedding. Then I 10 one more person that might still be in San Antonio. The girl I 11, Emily.

    I called Emily to see if she was still in town and she was! She came to my 12 and we drove to the wedding together. I was a little nervous 13 I liked her very much, but I didn't dare to ask her out. On the way, we had a great14 and we were both really excited for David and Katherine and couldn't 15 to get there.

    The wedding was beautiful. There was so much delicious food at the16, and because it was Easter, the entire wedding was 17 in very bright colors. The best part was that Emily and I danced all night together. I got to know her very well and we decided to go on a 18 when we 19 to San Antonio. My car breaking down was the best thing that 20 to me that Easter weekend!