下图是初中化学常见气体(氧气、氢气、二氧化碳)的制取和收集的实验装置,请按要求回

题型:问答题

问题:

下图是初中化学常见气体(氧气、氢气、二氧化碳)的制取和收集的实验装置,请按要求回答下面问题:

(1)若装置A、B组合,可以制取和收集的气体是______(填化学式,下同);若装置A、C组合,可以制取和收集的气体是______;若装置A、D组合,可以制取和收集的气体是______.

(2)有的同学认为装置E可以代替装置B、C、D收集气体,欲收集具备下面性质的气体,应如何使用装置E?

收集比空气密度大的气体:进气口为______(填“a”或“b”,下同);

(3)装置E还可以作为洗气瓶用于干燥某些气体,若干燥氧气,洗气瓶中应装入的试剂是______,进气口为______.

考点:实验室制取和收集气体的思路
题型:问答题
设向量a与b的夹角为θ,定义a与b的“向量积”:a×b是一个向量,它的模|a×b|=|a|•|b|sinθ.若a=(-
3
,-1)
b=(1,
3
)
,则|a×b|=______.
题型:问答题

下列80x86指令系统的寻址方式中,存取操作数的速度( )最快。

A.存储器直接寻址

B.寄存器寻址

C.寄存器间接寻址

D.寄存器相对寻址

题型:问答题

简述免疫功能缺陷者隐孢子虫病的临床特点。

题型:问答题

缩窄性心包炎

A.肺性发绀

B.心性混血发绀

C.淤血性发绀

D.缺血性发绀

E.混合性发绀

题型:问答题

I remember my math teacher Mr. Young very well. He stood out because the kids made fun of him. He was missing one of his fingers, and always pointed at students with his middle finger.

I was not very good at English and math. No matter how hard I tried, I just could not figure out why I did not understand what all the other kids found so easy to learn.

One day, I was told that if I got one more E on my report card, I would be taken to the" big prison for kids".

I tried really hard for weeks. I just couldn’t understand how to make different parts of members into whole things.

The day before report cards were to come out, I knew that Mr. Young would give me an E ,just like he always did.

I went to Mr. Young and told him that the orphanage was going to send me to the big prison if I got another E on my report card. He told me there was nothing he could do;it would be unfair to the other kids if he gave me a better grade than I had actually earned.

I smiled at him and said, "Mr. Young, do you know how the kids make fun of you because you’re missing your finger" He looked at me, moved his mouth to one side and said nothing.

"They shouldn’t do that to you because you can’t help having a finger, Mr. Young. Just like I can’t help not being able to learn numbers and stuff like that. "I said.

The next day, when I got my report card, I tucked it into one of my books. While on the school bus, I opened it : Geography, B+ ; Mechanical Drawing, C- ; English, D- ; History, C- ; Gym, B+ ; Art, C ; Math, D-.

That math grade was the most favorite one I ever received. Because I knew that someone in the world finally understood what it was like for me to be missing a finger inside my head.

Where may the boy live according to the passage()

A. In an orphanage.

B. In a big prison.

C. In the school dormitory.

D. In his home.

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