题干

在一密闭容器中,有甲、乙、丙、丁四种物质,反应前,他们的质量如白色条形图所示.反应结束后,他们的质量如黑色条形图所示.下列说法正确的是(  )

A:丙一定是该反应的催化剂

B:该反应为化合反应

C:甲、乙的相对分子质量之比一定为2:3

D:反应过程中甲和丁变化的质量比为2:1

上一题 下一题 0.0难度 选择题 更新时间:2018-06-09 11:10:14

答案(点此获取答案解析)

D

同类题1

根据短文内容,完成表格。

  Anderson, a Danish writer, is famous for his fairy tales(童话). Both children and adults love his stories. For example, The Ugly Duckling is well-known to people around the world. In fact, Andersen used to be an ugly duckling when he was young.

  In 1805, Andersen was born into a poor family in Denmark. As a young boy, he was tall and ugly and had a very big nose. His friends always made jokes about his big nose. Later, because of his father's death, little Andersen had to make a living by himself. He once

worked as a dressmaker and made money in a theater.

 The difficulties in life helped him create his fairy tales. In The Little Mermaid, he talked about love and sacrifice(牺牲).In Emperor's New Clothes, He made fun of the authority(权威).

 Besides creating stories, Andersen also loved travelling. His famous saying was, "To travel is to live."

 Today, Andersen's fairy tales have been printed into over 100 languages. The Hans Christian Andersen Award is named after him. It's the highest award to give a writer of children's books.

King of Fair Tales and His Fantasy Lands

Personal Experiences

  1. He was born into ____  in Denmark, in 1805.
  2. He was laughed at by his friends because of his looks.
  3. He lived a hard life after his father's death, ____  and making money in a theater.
  1. He wrote about his trips while travelling to many countries.

Master works

  1. The Ugly Duckling is based on his own experiences.
  2. ____shows love and sacrifice.
  3. In Emperor's New Clothes,____ the authority.

Achievement

Andersen made great contributions to ____