题干

下列化学实验操作中,不正确的是    

A:实验室制取气体时,先检查装置的气密性

B:实验室制取二氧化碳气体,不宜用排水法收集

C:用托盘天平称量药品时,先调节天平平衡,后称量

D:为了防止液体流出,将胶头滴管伸入试管口以内滴加液体

上一题 下一题 0.0难度 选择题 更新时间:2018-01-26 11:03:05

答案(点此获取答案解析)

D

同类题1

阅读下列内容,从每小题所给的A、B、C、D四个选项中选出一个最佳答案。

    When I was young, I wanted a dog. But my parents always said I was too young. They suggested getting another kind of pet. But I wanted a dog, so I waited. When my parents thought I was old enough at last, I got Luke. From then on, I learned that having a dog was really hard work.

                                                                                                                                 -Kate

Cinder and I became good friends about a year ago. Cinder is my dog. I named her Cinder because my name is Cindy. I think the name Cinder sounds nice. I got the dog on my twelfth birthday. The next morning, I went to the library to find out some information about how to take care of the dog.

-Cindy

I'm in Grade Four at the Blake School. My pet hamster(仓鼠), Lightning, lives in our classroom. She is brow n and white. I got my hamster two years ago. My friend Jason and I gave each other a hamster for our birthdays. I brought my hamster to school once and the other kids liked her. I decided to leave her there, because my parents hated having Lightning in the house.

                                                                                                                               -David