试题与答案

教材193页探究酸碱中和反应: 所用试剂:稀盐酸、酚酞试液、氢氧化钠溶液. 操作

题型:问答题

题目:

教材193页探究酸碱中和反应:

所用试剂:稀盐酸、酚酞试液、氢氧化钠溶液.

操作过程:在盛有氢氧化钠溶液的试管中,滴加2-3滴酚酞试液,测定此时液体温度为T1℃,然后向试管中逐滴加入稀盐酸溶液,边滴边振荡直到溶液刚好变成无色,再测定溶液温度为T2℃.我校学生在实际实验操作过程中可能有部分学生操作时试剂用量过多,老师将学生倒的废液收集起来发现此时液体的颜色是无色的.请你判断:

(1)正确操作时,实验测定的结果温度T1℃______T2℃(填“>、<或=”)

(2)老师收集的废液是无色的,你认为老师收集的废液可能呈______性,理由是______.

(3)请你设计实验验证此时废液显什么性?(要求:所选试剂属于不同种类,至少写出四种方法,请把正确答案填入下表)

操作方法实验现象和结论
1、取样后滴加紫色石蕊试液 
2、 
3、 
4、 

答案:

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Without plants, people could not live. We eat plants. 小题1:   And we need plants for another reason: we need them because they are beautiful.

小题2:      Imagine no flowers with their sweet smell, their beautiful colors and their lovely shapes. Imagine, when the wind blows, we’re not able to hear the leaves in the trees or watch the branches swing from side to side.

小题3:     That is why we have parks full of trees and flowers. That is why people always like houses with room for some grass or a garden.

Do you talk to your plants? 小题4:     Peter Tompking and Christopher Bird wrote a book called The Secret Life Of Plants, telling of an experiment in which two seeds were planted in different places. While the plants were growing, one plant was given love and hopeful ideas. The other plant was given only hopeless ideas. 小题5:    Under the earth it had more and longer roots; above the earth, it had a thicker stem and more leaves. While the other one nearly stopped growing.

A.Plants get energy from the sun.

B.Do you give them love and attention?

C.After six months, the deserted plant faded away.

D.After six months, the beloved plant was bigger.E. We take in oxygen that plants make.

F. Everywhere people need beautiful plants.

G. Imagine a world with no plants.

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