下列除去杂质的操作不正确的是[ ] 物质(杂质) 除杂试剂  提纯方法 A.F

题型:选择题

问题:

下列除去杂质的操作不正确的是[ ]

  物质(杂质)  除杂试剂   提纯方法

A.FeCl2(CuCl2)  水、铁粉  过滤、蒸发、结晶

B.NaCl(Na2CO3) 稀盐酸   蒸发、结晶

C.CO2(CO)   石灰水     干燥

D.MnO2(KCl)    水    过滤、洗涤、干燥

考点:物质的除杂
题型:选择题

A dog has a piece of meat in his mouth. He’s going to eat it at home. As he is walking on a bridge, he looks down and sees himself in the river. That dog looks like him and he has a piece of meat in his mouth, too. The dog thinks it’s another dog. So he says to himself, “I want to eat more meat. I must make him run away from here and get the meat in his mouth. Then I can have two pieces.” He opens his mouth to bark. That dog in the water barks at him. Suddenly, his meat goes down into the water. The dog is so angry, he jumps into the water to catch the other dog.

小题1:How many dogs are there in the river?

A.None.

B.one.

C.Two.

D.We don’t know.小题2:The dog in the water         .

A.is more hungry

B.is very angry at him

C.is very kind

D.is not a real dog at all小题3:What does the story tell us?

A.The greedy(贪心的) dog gets nothing at last.

B.The dog is a clever one.

C.A dog always wants two pieces of meat.

D.The dog can get two pieces of meat.

题型:选择题

本世纪我国人口老龄化发展趋势预计分为()几个阶段.

A.快速老龄化阶段

B.加速老龄化阶段

C.重度老龄化阶段

D.适度老龄化阶段

题型:选择题

某非金属氧化物RO2中氧元素的质量分数50%,计算R的相对原子质量.______.

题型:选择题

仲裁协议、行政复议申请均可以是书面形式的,也可以是口头形式的。 ( )

题型:选择题

对联是利用汉字特征撰写的一种民族文体,一般都要押韵。

更多题库