问题 选择题

用如图所示的装置进行实验,反应一段时间后断开K,向右侧烧杯中加入0.1 mol CuO后CuSO4溶液恰好恢复到反应前的浓度和pH。下列说法中不正确的是  (  )

A.铜棒为正极,其电极反应式为:2H+2e====H2

B.烧杯右侧碳棒为阴极,其电极表面有红色物质析出

C.反应中消耗锌的质量为13 g

D.导线中通过电子的物质的量为0.2 mol

答案

答案:C

题目分析:A、锌比铜活泼,锌是负极,铜是正极,溶液中的氢离子放电,A正确;B、烧杯右侧碳棒与电源的负极相连为阴极,溶液中的铜离子放电,其电极表面有红色物质析出,B正确;C、反应一段时间后断开K,向右侧烧杯中加入0.1 mol CuO后CuSO4溶液恰好恢复到反应前的浓度和pH,这说明惰性电极电解硫酸铜溶液时阳极是氢氧根放电产生氧气,阴极是铜离子放电析出铜,电极反应式分别为4OH--4e-=2H2O+O2↑、2Cu2++4e=2Cu。根据原子守恒可知,析出铜的物质的量是0.1mol,则反应中转移电子的物质的量是0.2mol。根据电子守恒可知锌失去电子的物质的量也是0.2mol,消耗锌的质量是0.1mol×65g/mol=6.5g,C不正确;D、导线中通过电子的物质的量为0.2 mol,D正确,答案选C。

阅读理解

Friends are important to the children. Research shows that children who have no friends can suffer from difficulties later in life. Friendship provides children with more than just fun. In making friends, children learn how to get in touch with the others and solve problems. Having friends even does good to children’s study for they can help each other during the class.

If the parents care about their children whether they made many friends,what matters is that the child is comfortable and happy with his friends. Parents need to understand the steps children take in building friendships. First of all, be a friend to your child. Good friendships start at home. Children begin to develop the necessary ability to go out and meet others through getting with their parents. Greet the child warmly and let him know you are glad to see him. Children learn a lot from how their parents stay with them and other people.

Teach children how to solve conflicts(争端). Being able to work out conflicts is an important skill in getting along with others. If parents know the children have a conflict, let them work it out on their own. Only step in if it is really necessary, for example, an argument is getting physical.

Give children chances to practice staying together. Have children play games that require team work and group problem solving skills. For example, races are fun and provide plenty of practice in teamwork. “In what ways didn’t you work well together? What might you do differently next time?” For these ideas, see books such as Games Book by Terry Orlick, Energizers by Carol Apacki, and Team-Building Activities for Every Group by Alanna Jones.

Encourage children to show thanks to the others. The parents can encourage children to do this by setting the example for them.

小题1:According to the article, if one child has no friend, he will               .

A.have some troubles in the future

B.worry about everything in the future

C.not know the importance of making friends

D.not find anybody to help him小题2:Friendship can be helpful to the children EXCEPT              .

A.providing a lot of fun

B.getting in touch with others

C.solving the problems

D.helping to trick in the exams小题3:The writer’s purpose of writing the article is to               .

A.tell what parents should do to help the children make friends

B.show friends even does good to children’s study during the class

C.tell the parents need to understand the steps of children’s friendship

D.show how important the friendship is to the children小题4:When the children disagree with each other, the parents should                 .

A.let them fight with each other until they find who is the winner

B.do nothing to the children and believe in their abilities

C.let them work it out by themselves and help if necessary

D.talk with them and try to find good ways to stay together

单项选择题 共用题干题