问题 实验题

某实验小组用工业上废弃固体(主要成分Cu2S和Fe2O3)混合物制取粗铜和Fe2(SO4)3晶体,设计的操作流程如下:

(1)除酒精灯和铁架台或三脚架外,①中所需的容器和夹持仪器分别为________、 ____________,①和⑥中都用到的仪器为____________________ ;

(2)试剂x的化学式为__________;x与溶液B反应的离子方程式为__________________;

(3)某同学取少量的溶液B向其中加入过量的某种强氧化剂,再滴加KSCN溶液,发现溶液变红色,放置一段时间后,溶液褪色,该同学猜测溶液褪色的原因是溶液中的SCN被过量的氧化剂氧化所致。现给出以下试剂:1.0 mol/L硫酸、1.0 mol/L NaOH溶液、0.1 mol/L Fe2(SO4)3溶液、20%KSCN溶液、蒸馏水。请你设计合理实验验证乙同学的猜测是否合理。简要说明实验步骤和现象_______________________________________________;  

(4)某同学用实验制得的Fe2(SO4)晶体配制0.1 mol/L 的Fe2(SO4)3溶液,在称量出Fe2(SO4)3晶体后,溶解该晶体的具体操作为_____________。

答案

(1)坩埚;坩埚钳;玻璃棒

(2)H2O2;2Fe2+ + H2O+ 2H+  = 2Fe3+ + 2H2O

(3)取少量褪色后的溶液于试管中,逐滴加入过量的20%KSCN溶液,如溶液变红色,说明乙同学的猜测是合理的,如不变红色,说明猜测不合理。(或滴加过量的0.1 mol/L Fe2(SO4)3溶液,如溶液不变红色,说明合理,若变红色,说明猜测不合理)

(4)将称量的晶体置于烧杯中,加入适量的稀硫酸和蒸馏水,用玻璃棒搅拌

阅读理解

阅读理解

     Boys need friends, suffer when they don't believe they have any, and worry over the ups and downs of relationships. Many adults believe that somehow boys need friends less than girls do, in truth, though, no

boy is an island; boys value their friends throughout childhood and adolescence and are happier and

healthier when they have solid relationships with peers(同龄人).

     Despite the common belief that girls are better at relationships, most boys consider their friends a very

important part of their lives, and boys may actually be better at keeping friendships than girls are. A recent study of 10 to 15yearold boys and girls found that girls' friendships are actually more fragile. Girls tend to

say and do hurtful things to each other more frequently than boys, and girls are more hurt by the end of a

friendship.

     Boys are the living definition of the phrase "peer group"; they love games with rules, competition, and doing things together. Boys seem to enjoy, even need the opportunity to test themselves against others, and many lasting friendships begin in karate(空手道) class or on the basketball court. Competence and skill

are widely respected; being picked last for a team or left out altogether is an experience that can haunt

(萦绕心头) a boy for years.

     As boys mature, the friendship becomes even more important, and it frequently widens to include girls. During the teen years, friends can become the most important part of a boy's life-and a part in which his

parents are not included. The confusion of being a teenager leads boys to form close bonds with friends.

There is the sense for many boys that a friend is someone who is "always there for me", someone he can

trust. They may be partners in crime or partners in study, but the friendship of adolescent boys can run

surprisingly deep.

1. The common belief of adults is that boys________.

A. don't care about others as much as girls

B. don't value friendship as much as girls

C. have the same friendship as girls

D. have healthier friendship than girls

2. According to the text, boys' friendship________.

A. is usually built around active play

B. tends to be in small groups

C. can bear mutual hurt between friends

D. doesn't suffer from failure

3. The author mentions the study in the second paragraph to prove ________.

A. many people believe girls are better at relationships

B. most boys consider their friends very important

C. boys may be better at keeping friendships than girls

D. boys may be more active in a friendship

4. As a boy gets older, he tends to________.

A. widen his circle of friends to include different kinds of people

B. shift his focus from his friends to himself

C. leave his parents out of his friendship

D. be confused about what a friendship is

5. What's the best title for the text?

A. Friendships between Boys and Girls

B. Boys and Their Friendship

C. Childhood and Adolescent Friendship

D. Tips on Making Friends with Boys

单项选择题