问题 问答题 简答题

化学除盐的原理是什么?

答案

参考答案:

化学除盐是利用离子交换树脂的可离解离子对水中离子产生交换反应的特性;阳离子交换树脂交换水中钙、镁、钠等离子放出H+;阴离子交换树脂再交换水中二价硫酸根离子、氯离子、硅酸根离子等阴离子放出OH-;H+和OH-结合生成水,从而达到去除水中盐类的目的。

阅读理解

     Jack sits in the coffee bar that looks at Jaffa Street listening to the sad, sad music playing on an old

tape recorder. "Oum Khalsoum", says one of the other men sitting in the coffee bar to nobody in

particular. "This is Oum Khalsoum singing".

Jack takes another sip of sweet mint(薄荷) tea and nods in agreement without saying anything. His uncle

lives in Egypt, and every time he visits him, he tells him the story of how he saw the well-known singer at

one of her concerts in Cairo in 1970, not long before she died. The song seems to go on forever, and it's

very sad. He thinks it's beautiful, but he doesn't want to hear it now. It's too sad for him. It makes him

think of his uncle in Egypt who he hasn't seen for many years now, and also about the reason why his

uncle lives in Egypt while his aunt lived in Lebanon and why he, on the other hand, lives in Jordan, and

why he is in Jerusalem now.

     His father died a few months ago. After that, he found that there were so many things that he had

wanted to ask his father, but had never asked . He realized that he knew very little about his own family,

and decided to try and find out more about the place where his father had grown up, and where his

grandparents (who had died when he was very young) were from.

     He has now spent a couple of days wandering around Jerusalem with an old, torn photograph in his

hand. The photograph shows the whole family, his grandparents standing proudly at the centre of a

group of four children in front of a house on a busy street. Next to the house there seems to be a garden

with what look like olive (橄榄色) trees in it.

     Jack, though, can't find anywhere in this modern Jerusalem that looks much like the street or the

house where the photograph was taken. He feels sadder than the sad song playing in the cafe, thinking

now that he might never find the place where his father had been born and the place where his

grandparents had lived until they moved away in 1947.

1. According to the passage, the sad music make Jack think of _____.

A. His uncle

B. His father

C. His mother

D. His family

2. We can know that Jack used to live______.

A. in Egypt

B. in Jerusalem

C. in Jordan

D. in Cairo

3. Jack tried to find out that_____.

A. Where his father lived in the past

B. Where his grandparents was from

C. He wanted to know more about his family

D. All of above

4. It is implied that______.

A. Jack wants his family to lead a good life

B. Jack has a photograph taken with his family

C. Jack looks happy and enjoys love from his family

D. Jack is a lonely man and knows little about his father

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