火箭推进器中盛有强还原剂液态肼(N2H4)和强氧化剂液态双氧水.当它们混合反应时

题型:填空题

问题:

火箭推进器中盛有强还原剂液态肼(N2H4)和强氧化剂液态双氧水.当它们混合反应时,即产生大量氮气和水蒸气,并放出大量热.已知0.4 mol液态肼与足量液态双氧水反应,生成氮气和水蒸气,放出 256.652 kJ的热量.

(1)反应的热化学方程式为____________________.

(2)又已知H2O(l)==H2O(g) ΔH=+44 kJ/mol,由16 g液态肼与液态双氧水反应生成液态水时放出的热量是________kJ.

(3)此反应用于火箭推进,除释放大量热和快速产生大量气体外,还有一个很大的优点是________________.

考点:热化学方程式大气污染、改善大气质量化学反应热的计算
题型:填空题

At school many things happen to us. We may feel excited when we have success in a school play. We may feel sorry if we lose an important game. We want to remember all the important things in our lives.

How to keep the memory? Our English teacher, Miss Wang, taught us a good way of remembering things to make our own yearbook. What is a yearbook? A yearbook is a kind of book which is used to keep the memory of exciting moments. It’s usually made at the end of the year.

Last December, we began to make our yearbook. First we chose the persons who did something special, then some students interviewed (采访) them, some wrote down their stories, others took photos of them. Everyone in our class had something to do. Finally our teacher helped us to put the things together. We had our first yearbook.

All of us put a lot of love into making the yearbook. It is so wonderful that not only the students but also our parents and teachers will remember the special time for ever.

小题1:When we have success in a school play, we may feel ______.

A.sorry

B.angry

C.excited

D.interested小题2:Miss Wang’s good way of remembering things is to ______.

A.buy a new book

B.write down stories

C.take a lot of photos

D.make a yearbook小题3:A yearbook is made to ______.

A.keep the memory

B.take notes

C.do our homework

D.remember English words小题4:Usually a yearbook is made in ______.

A.January

B.February

C.May

D.December小题5:We made our first yearbook ______.

A.without any help

B.without putting our love into it

C.with the help of our teacher

D.with the help of our parents

题型:填空题

美国2004年2月零售业平均库存是8520.2亿美元,2月销售额是6816.16亿美元,求2月的存销比率,并说明此存销比率代表的意义。

题型:填空题

下列关于黄芩"清热燥湿、泻火解毒"功效的药理作用,错误的是()

A.镇静

B.解热

C.保肝利胆

D.抗动脉粥样硬化

E.抗炎

题型:填空题

根据骨的成因,病理骨折属于()。

A.骨质疏松症骨折

B.重物撞击处骨折

C.远离受力处的骨折

D.反复长期轻微外力引起骨折

E.以上均是

题型:填空题

溯源性就是量值传递的()过程。

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