题目内容

【题目】在实验室测定空气中氧气的含量实验,能否用硫代替红磷?为什么?

________________________________________________________________________

【答案】不能用硫代替红磷,因为硫在空气中生成的二氧化硫是气体,不能使集气瓶内的气压减小

【解析】

试题分析:因为硫在空气中生成的二氧化硫是气体,不能使集气瓶内的气压减小所以不能用硫代替红磷。

练习册系列答案
相关题目

【题目】A

In a small town, there lived a doctor. He was good and kind. He was ready to go and help people. People always went to him when they were ill.

Many years later, the doctor began to forget things. The people were afraid and little by little, they stopped going to him. The doctor saw his business wasnt as good as before. He thought, Well, if I were the patient, Id be afraid to go to me too. Maybe its time for me to stop being a doctor. But if this town has no doctor, what will the people do when they become ill?

His wife heard him talking to himself and said, Why dont you find a young doctor to_take_your_place? Then people will have another good doctor to take care of them and I will get my husband back. The doctor did as what his wife said. He found a very good young doctor to help the people. The doctor and his wife then had time to take long walks together, go dancing, go traveling and spend the rest of their days together.

【1】 This story is about __________.

A. a husband B. a wife C. a patient D. a doctor

【2】The __________ always went to see the doctor because he was good and kind.

A. friends B. parents C. patients D. children

【3】The doctors business wasnt as good as before because __________.

A. he was always ready to help people B. people were afraid of him and his wife

C. he was old and forgetful D. there was a very good young doctor

【4】The expression to take your place in the third passage means __________.

A. to take you home B. instead of you C. to take care of you D. to help you

【5】 Which of the following is NOT true?

A. The old doctor agreed with what his wife said.

B. The old doctor was still busy working at the doctors at last.

C. The old doctor found a good young doctor.

D. The old doctor and his wife were very happy at last.

违法和不良信息举报电话:027-86699610 举报邮箱:58377363@163.com

精英家教网