问题 问答题

已知A、B、C、D、E、F、G、H、I九种物质,A、B、D、E焰色反应均为紫色(透过蓝色钴玻璃),G是一种单质,I是一种化合物,H是一种淡黄色固体,它们的转化关系如图所示.请回答下列问题:

(1)B、D、I的化学式是B______   D______    I______

(2)写出H的一种用途______

(3)写出A受热分解的化学方程式______

(4)若H与C反应固体增重4.2g,则参加反应的C气体在标准状况下的体积为______ L.

答案

A、B、D、E焰色反应均为紫色,说明都含有K元素,其中B能与二氧化锰在加热条件下反应生成气体F,应为KClO3的分解反应,则B为KClO3,E为KCl,F为O2,H是一种淡黄色固体,应为Na2O2,则G为Na,C为气体,能与过氧化钠反应生成氧气,则应为CO2,则A为KHCO3,D为K2CO3,I应为HCl,则

(1)由以上分析可知B为KClO3,D为K2CO3,I为HCl,故答案为:KClO3;K2CO3;HCl;

(2)H为Na2O2,可与水或二氧化碳反应生成氧气,可用于呼吸面具中和潜水艇里作为氧气的来源,具有氧化性,可用于漂白织物,

故答案为:可用于呼吸面具中和潜水艇里作为氧气的来源(或用于漂白织物等);

(3)KHCO3分解生成K2CO3、H2O和CO2,反应的方程式为2KHCO3

  △  
.
 
K2CO3+H2O+CO2↑,

故答案为:2KHCO3

  △  
.
 
K2CO3+H2O+CO2↑;

(4)根据反应的方程式计算:2Na2O2+2CO2=2Na2CO3+O2↑△m

                           156g   44.8L 212g         56g

                                   V                 4.2g

则V=

44.8L×4.2g
56g
=3.36L,

故答案为:3.36.

阅读理解

It was Monday,Mrs Smith’s dog was hungry,but there was not any meat in the house.

Considering that there was no better way,Mrs Smith took a piece of paper,and wrote the following words on it:”Give my dog half a pound of meat.” Then she gave the paper to her dog and said gently:”Take this paper to the butcher(卖肉者),and he is going to give you your lunch today.”

Holding the piece of paper in its mouth,the dog ran to the butcher’s shop.It gave the paper to the butcher.The butcher read it carefully ,he was sure that it was really the lady’s handwriting and presently did as he was asked to.The dog was very happy,and ate the meat up immediately.

At midnight the dog came to the shop again.It gave the butcher a piece of paper again.After reading it ,he gave it half a pound of meat once more.

The next day the dog came again exactly at midday.And as usual it brought a piece of paper in the mouth.This time the butcher did not take a look at the paper,and gave the dog its meat,for he had regarded the dog as one of his customers.

But the dog came again at four o’clock.And the same thing happened once again.To the butcher’s more surprise ,it came for the third time at six o’clock,and brought with it a third piece of paper.The butcher felt a bit puzzled.He said to himself,”This is a small dog.Why does Mrs. Smith give it so much meat to eat today?”

Looking at the piece of paper,he found that there were not any words on it!

小题1:It seemed that the dog knew well that the paper its master gave it______.

A.might do it much harm

B.could do it much good

C.would give the butcher some meat

D.was worth many pounds小题2:The butcher did not give any meat to the dog______.

A.when he found the words on the paper were not very clear

B.because he happened to have sold out all the meat in his shop

C.until he was paid enough by Mrs Smith

D.before he felt sure that the words were really written by Mrs Smith小题3:From its experience,the dog found that______.

A.a piece of paper could bring him half a pound of meat

B.only the paper from Mrs Smith’s words on it could bring it meat

C.the butcher would give it meat whenever he saw it

D.Mrs Smith would pay for the meat it got from the butcher小题4:At the end of the story you’ll find that______.

A.the dog was clever enough to write on the paper

B.the butcher found himself cheated by the smart animal

C.the dog dared not go to the butcher’s any more

D.the butcher was told not to give any meat to the dog

单项选择题 A1/A2型题