问题 选择题

白玉的化学式可用CaxMgySipO22(OH)2表示(也可用Ca、Mg、Si、H的氧化物表示),Si为+4价。

(1)取8.10g白玉粉末灼烧至恒重,固体减少了0.18g,则白玉的摩尔质量为       g/mol.

(2)另取4.05g白玉粉末加入1mol/L的盐酸100mL充分溶解, 过滤,得到不溶的非金属氧化物2.40g.将滤液和洗涤液合并后往其中加入足量的铁屑,得到气体336mL(标准状况).则

①p=      ;

②白玉的化学式为:

答案

(1)810(1分)(2)①8(2分)②Ca2Mg5Si8O22(OH)2(2分)

(1)可表达为   CaxMgySipO22(OH)2  → H2O

M                 18

8.10              0.18

解得M=810

(2)①可表达为   CaxMgySipO22(OH)2  →  pSiO2                       

810                 60p

4.05                 2.40             

解得p=8

②有2种表达,一是电荷守恒(化合价代数和为0),再根据式量,

可列式  2x+2y+8×4-22×2-1×2="0    " 40x+24y+24×8+22×16+2×17=810

求得的化学式为Ca2Mg5Si8O22(OH)2(或2CaO·5MgO·8SiO2·H2O )

单项选择题
阅读理解

阅读理解。

     One fine day, an old couple around the age of 70, walks into a lawyer's office. Apparently, they are

there to file a divorce.Lawyer was very puzzled, after having a chat with them, he got their story.

     This couple had been quarreling all their 40 years of marriage nothing ever seems to go right.

     They hang on because of their children, afraid that it might affect their up-bringing.Now, all their

children have already grown up, have their own family, there's nothing else the old couple have to worry

about, all  they wanted is to lead their own life free from all these years of unhappiness from their marriage,

so both agree on a divorce.

     While they were signing the papers, the wife told the husband. "I really love you, but I really can't carry

on anymore, I'm sorry."

      "It's OK, I understand." said the husband.

      Little did she know that, over the years, the husband has been trying all ways to please her, little did she

know that drumsticks were the husband's favorite.

     Little did he know that she never thought he understands her at all, little did he know that she hates

drumsticks even though all he wants is the best for her.

     That night, both of them couldn't sleep, toss and turn, toss and turn.After hours, the old man couldn't

take it anymore, he knows that he still loves her, and he can't carry on life without her, he wants her back,

he wants to tell her, he is sorry, he wants to tell her,"I love you."

     He picked up the phone, started dialing her number. Ringing never stops.He never stops dialing.

     On the other side, she was sad, she couldn't understand how come after all these years, he still doesn't

understand her at all, she loves him a lot, but she just can't take it any more.Phone's ringing, she refuses to

answer knowing that it's him. "I want to keep it this way, if not I will lose face." She thought.Phone is still

ringing.She has decided to pull out the cord.

     Little did she remember, he had heart problems.

     The next day, she received news that he had passed away. She rushed down to his apartment, saw his

body, lying on the couch still holding on to the phone.He had a heart attack when he was still trying to get

thru (接通) her phone line.

1. The old couple wanted to file a divorce because ______.

A. they had no child.

B. their children didn't like them.

C. they didn't understand each other actually.

D. the old man didn't love the old woman.

2. Why didn't they file a divorce before they were at the age of 70?

A. Because they were loving each other then.

B. Because they had no time to lawyer's office.

C. Because they wanted to make their divorce open.

D. Because they didn't wish to affect their children's up-bringing. 

3. According to the passage we can know that ______.

A. the old man still loved his wife really.

B. the wife didn't love her husband at all.

C. their children still lived with old couple.

D. they were in harmony over 40 years.

4. After the last paragraph the old woman would be _______.

A. wild with joy

B. wild with grief

C. unconcern about it

D. angry at that