问题 选择题

下列溶液中的Cl-物质的量浓度与50 mL 1 mol·L-1氯化铝溶液中的Cl-的物质的量浓度相等的是(    )

A.150 mL 1 mol·L-1氯化钠

B.75 mL 2 mol·L-1氯化铵

C.150 mL 3 mol·L-1氯化钾

D.75 mL 1.5 mol·L-1氯化铝

答案

答案:C

熟知物质所对应的化学式即可知各微粒之间的包含关系,只找Cl-物质的量浓度是3 mol·L-1的,和前面的体积无关。

阅读理解

The idea of being able to walk on water has long interested humans greatly. Sadly, biological facts prevent us ever accomplishing such a thing without artificial aid --- we simply weigh too much, and all our mass pushes down through our relatively small feet, resulting in a lot of pressure that makes us sink.

However, several types of animals can walk on water. One of the most interesting is the common basilisk Basilicus basilicus, a lizard(蜥蜴)native to Central and South America. It can run across water for a distance of several meters, avoiding getting wet by rapidly hitting the water’s surface with its feet. The lizard will take as many as 20 steps per second to keep moving forward. For humans to do this, we’ll need huge feet that we could bring up to our ears in order to create adequate “hitting.”

But fortunately there is an alternative: cornflour. By adding enough of this common thickening agent to water (and it does take a lot), you can create a “non-Newtonian” liquid that doesn’t behave like normal water. Now if the surface of the water is hit hard enough, particles(粒子)in the water group together for a moment to make the surface hard. Move quickly enough and put enough force into each step, and you really can walk across the surface of an adequately thick liquid of cornflour.

Fun though all this may sound, it’s still rather messy and better read about in theory than carried out in practice. If you must do it, then keep the water wings handy in case you start to sink --- and take a shower afterward!

小题1:Walking on water hasn’t become a reality mainly because humans _______.

A.are not interested in it

B.have biological limitations

C.have not invented proper tools

D.are afraid to make an attempt小题2:What do we know about Basilicus basilicas from the passage?

A.It is light enough to walk on water.

B.Its huge feet enable it to stay above water.

C.It can run across water at a certain speed

D.Its unique skin keeps it from getting wet in water小题3:What is the function of the cornflour according to the passage?

A.To create a thick liquid.

B.To turn the water into solid.

C.To help the liquid behave normally.

D.To enable the water to move rapidly.小题4:What is the author’s attitude toward the idea of human’s walking on water?

A.It is risky but beneficial.

B.It is interesting and worth trying

C.It is crazy and cannot become a reality

D.It is impractical; though theoretically possible

名词解释