问题 选择题

下列关于纯净物、混合物、强电解质、弱电解质和非电解质的正确组合是(  )

纯净物混合物强电解质弱电解质非电解质
A盐酸水煤气硫酸醋酸干冰
B氢氧化钡蔗糖溶液硫酸钡醋酸三氧化硫
C胆矾石灰水苛性钾碳酸钙
D重钙普钙氯化钠氢氧化铁氢气

A.A

B.B

C.C

D.D

答案

纯净物:有一种物质组成.混合物:由两种或两种以上的物质组成.在水溶液里或熔融状态下完全电离的是强电解质,部分电离的是弱电解质;在水溶液里或熔融状态下不导电的化合物是非电解质,

A、盐酸是混合物,故A错误.

B、各项符合条件,故B正确.

C、碳酸钙是电解质,故C错误.

D、重钙是混合物,氢气是单质,故D错误.

故选B.

阅读理解

阅读理解。

     On the first day of my new high school, I almost had a nervous breakdown. Everything about the school

seemed so difficult. When I got home, my parents said, "You're nervous and that's okay. Everyone is afraid

of high school." I denied it. I wanted to be strong, so I refused to let anyone know about my fear, even my

closest friends.

     On the first day I was late for every class and was constantly lost. The school seemed like a puzzle that I

couldn't figure out. Was this how the whole year was going to be? I didn't think I could rise to this challenge,

especially carrying a huge backpack that I could hardly lift. It was so big that I could knock someone out with

it! The schoolmates seemed to regard me as a fool, and they were probably right.

     Despite my fears, after the first week I finally had my schedule figured out. With the exception of falling up

and down the stairs a couple of times and getting laughed at, high school was turning out to be not so bad. It

was actually much better than middle school and much more challenging.

     Since then, I've been elected vice president of my class, which wasn't much of a victory since only three

people ran for the four positions.

     It is normal to be scared about a new school. Take a deep breath and relax. High school is something that

any student can overcome. Make sure you participate in some out-of-class activities because you'll find it easier

to make friends. Try to do your best, even if it isn't straight A's.

     Most important of all, be who you are, whether you're a "fool", an athlete, or a lower grader. Don't try to

pretend to be someone you're not. Now you know the true secrets of high school.

1. The main reason for the author's fear on his first day is that _____.[ ]

A. he was unable to work out the puzzle

B. his schoolmates were unfriendly to him

C. he was not familiar with the new surroundings

D. his schoolbag was too heavy for him to carry

2. From the author's first day experience we can infer that _____. [ ]

A his home was far from the school 

B. he got to school after classes began

C. he didn't get any school schedule

D. he didn't know the right way to class

3. After his first week at school, the author _____. [ ]

A. was still not accustomed to the schedule

B. gradually adjusted himself to the new school

C. found high school not so challenging as he had imagined 

D. ran for president of his class against three other students

4. According to the passage, the secret of the author's success lies mainly in _____. [ ]

A. making more friends

B. getting more A's at school

C. being who he really is

D. joining in out-of-class activities

填空题