问题 选择题

下列物质的鉴别方法错误的是                                         

A.用肥皂水鉴别软水和硬水

B.用带火星的木条鉴别空气和氧气

C.用灼烧法鉴别棉纤维和羊毛纤维

D.用酚酞溶液鉴别稀盐酸和稀硫酸

答案

答案:D

考点:

专题:生产、生活、环保类简答题;结合课本知识的信息;物质的鉴别题.

分析:肥皂水与软硬水时泡沫的多少不同;氧气能使带火星木条复燃;灼烧羊毛纤维时产生焦羽毛的气味;酚酞试液遇酸不变色,利用这些基础知识可解决此题.

解答:解:A、肥皂水遇到硬水时泡沫较少,软水较多,故此选项说法正确.

B、氧气能使带火星的木条复燃,空气不能,故此选项说法正确.

C、灼烧棉纤维与羊毛纤维时,羊毛纤维会产生焦羽毛味的气体,棉纤维没有,故此选项说法正确.

D、酚酞遇酸不变色,用酚酞无法区分两种酸,故此选项说法错误.

故选D

点评:此题是一道鉴别题,解决的关键是能利用两物质的特点对其进行分析判断,找到相关的选项,属基础性知识考查题

单项选择题

An eight-year-old child heard her parents talking about her little brother. All she knew was that he was very sick and they had no money left. When she heard her daddy say to her (1) mother," (2) a miracle can save him now", the little girl went to her bedroom and took out her piggy bank. She (3) all the change out on the floor and counted it carefully. Then she (4) her way six blocks to the drugstore.

"And what do you want" asked the shopkeeper. "It’s (5) my little brother," the girl answered back. "He’s really, really sick and I want to buy a (6) . His name is Andrew and he has something (7) growing inside his head and my daddy says only a miracle can save him. " "We don’t (8) miracles here, child. I’m sorry." the chemist said, smiling (9) at the little girl.

In the shop was a (10) customer. He stooped down and asked the little girl, "What kind of miracle does your brother (11) " "I don’t know," she replied. "He’s really sick and mommy says he needs (12) . But my daddy can’t pay for it, so I have brought my (13) .""How much do you have" asked the man. "One dollar and eleven cents, (14) I can try and get some more," she answered quietly. "Well, what a coincidence," smiled the man. "A dollar and eleven cents—the (15) price of a miracle for little brothers. (16) me to where you live. I want to see your brother and (17) your parents. "

That well-dressed man was Dr Carlton Armp, a doctor. The operation was completed without any (18) and it wasn’t long before Andrew was (19) again. The little girl was happy. She knew exactly how much the miracle cost—one dollar and eleven cents—also the (20) of a little child.

13().

A.change

B.wish

C.idea

D.dream

填空题