问题 选择题

下列示意图与对应的反应情况正确的是(  )

A.含0.01 mol KOH和0.01 mol Ca(OH)2的混合溶液中缓慢通入CO2B.NaHSO4溶液中逐滴加入Ba(OH)2溶液C.KAl(SO4)2溶液中逐滴加入Ba(OH)2溶液D.NaAlO2溶液中逐滴加入盐酸
 

答案

答案:B

解答本题的关键是正确分析反应实质,注意反应物量的多少对反应的影响。A中通入的二氧化碳先与氢氧化钙反应生成沉淀,再与氢氧化钾反应,最后与生成的碳酸钙反应,故沉淀的量应是先增大再不变,最后减小为零,A不正确;C中先生成硫酸钡和氢氧化铝沉淀,随后硫酸钡的量增多,但氢氧化铝在溶解,最后沉淀的量不变,在图像中应有三条线段,C不正确;D中应是先生成氢氧化铝沉淀,后沉淀逐渐消失,D不正确。

解答题
阅读理解

According to a new education survey, student safety has become a big problem. Nearly 50 percent of the students say they are worried about robbery on the way to and from school. Now in many big cities in China,some schools have taught an unusual lesson. self-protection;Students like this lesson as there are no exams or boring classes. And they can learn how to save lives and know how to stop danger before it really happens.

Chen Haoyu,a teacher at Beijing No. 25 Middle School and a self-protection expert,gives young students advice on how to deal with danger.

If you are robbed, keep calm. If you cannot cry for help or run away, give the robber your money, try to remember what the robber looks like and tell the police.

If you are in a traffic accident and if you are hurt by a car, take down the car number;if it is a bicycle, try to contact your parents before you let the rider go. This is because you don’t know how seriously you are hurt.

Don’t stay in high places and keep away from trees if it is raining hard and there is lightning.

Get away as fast as you can when there is a fire.Put wet things on your body and try to find an exit. Do not take the lift!    

If someone is drowning and you can’t swim, don’t get into the water. Cry out for help.

Remember that danger is never as far away as you think. Take care of yourself at all times!

小题1:Why do students like the self-protection lesson?

A.Because there is advice on exams

B.Because they can learn how to protect themselves.

C.Because they like self-protection experts.

D.Because they have lots of exams during the lesson.小题2:The underlined word “contact” means_________.

A.end up

B.wait for

C.search for

D.get in touch with小题3:If your house is on fire, you must __________.

A.put dry things on your body

B.run quickly and take the lift

C.take everything you have and then run away

D.run away and find an exit as quickly as you can小题4:If you see a child fall into the river and you are not able to swim, you _______.

A.should telephone the doctor

B.can jump into the river and save him

C.can do nothing

D.should shout for help小题5:What’s the best title for this passage?

A.Protection

B.Advice on how to deal with danger

C.The popular lesson

D.An interesting lesson