问题 选择题

下列化学反应的离子方程式正确的是

A.用小苏打治疗胃酸过多:HCO32-+H===CO2↑+H2O

B.往碳酸镁中滴加稀盐酸:CO32-+2H===CO2↑+H2O

C.往澄清石灰水中通入过量二氧化碳:Ca2+2OH+CO2===CaCO3↓+H2O

D.氢氧化钡溶液与稀硫酸反应:Ba2+SO42-+H+OH===BaSO4↓+H2O

答案

答案:A

题目分析:碳酸镁难溶于水,应该用化学式表示,B不正确;C中CO2是过量的,生成物应该是碳酸氢钙,C不正确;D中应该是Ba2+SO42-+2H+2OH===BaSO4↓+2H2O,答案选A。

点评:该题是高考中的高频题,属于中等难度的试题,侧重对学生能力的培养和训练。该题需要明确判断离子方程式正确与否的方法一般,即(1)检查反应能否发生。(2)检查反应物、生成物是否正确。(3)检查各物质拆分是否正确。(4)检查是否符合守恒关系(如:质量守恒和电荷守恒等)。(5)检查是否符合原化学方程式,然后灵活运用即可。该题有助于培养学生分析问题、解决问题的能力。

阅读理解

As you grow rapidly through your teenage years, you will experience a lot lf changes.The changes may seem difficult and they may seem to happen quickly. Don’t panic! You will deal successfully with them! You are a young adult now!

With more responsibility, you will find more freedom to make your own choices. This is a time to be well informed about own choices. This is a time to be well informed about your choices so that you can make healthy balanced decisions that will help shape your future. You may already know your career path or you may have no idea at all what you want to do. Both situations are fine! Work hard and the right opportunity will present itself to you.

Young adulthood means greater freedom and more choices. You will probably want to be independent. But try not to shut your family out of your life. You should learn to think of others even though you are old enough to look after yourself. Your family have been with you since you came into this world.

It is also perfectly natural in this time for you to spend more time with your friends than your family. Choose your friends wisely. A true friend will stand by you no matter what happens.

This period is a part of the life cycle. There are some people who will be with you throughout life’s journey and there will be some people with whom you part and go separate ways. Leaving school can be hard. The reality is that you may not ever see all of your classmates again.

You are a young adult. It is your life. No one can live it for you. The choices that you make from now on will be your choices. So making the right choices will be important to you. Life is for living. Enjoy your life wisely!

小题1:The best title for this passage would be       

A.The Choices in Life

B.The Key to Success

C.Say Goodbye to the Past

D.Becoming a Young Adult小题2:Who do the underlined words “ some people”(Paragraph 5)probably refer to?

A.your parents

B.your classmates

C.true friends

D.your relatives小题3:The author thinks teenage years are      

A.a period of complete freedom

B.too hard for young people to get through

C.an important time for the young to make the right choices

D.a very important period for young students to leave their parents小题4:Who is the passage mainly written for?

A.Teenagers.

B.Teachers.

C.Young parents.

D.Adults.

单项选择题