1 mol CH4气体完全燃烧放出的热量为890 kJ，但当不完全燃烧生成CO和_爱下问搜题

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问题选择题

1 mol CH₄气体完全燃烧放出的热量为890 kJ，但当不完全燃烧生成CO和H₂O(l)时，放出的热量为607 kJ，如果1 mol CH₄与一定量O₂燃烧生成CO、CO₂、H₂O，并放出819.25 kJ的热量，则一定量O₂的质量为 (　　)

A．40 g

B．56 g

C．60 g

D．无法计算

答案

答案：C

题目分析：由题意可知，甲烷完全燃烧的热化学方程式为CH₄(g)+2O₂(g)＝CO₂ (g)+2H₂O（l） ΔH=－890 kJ·mol^-1；同理不完全燃烧的热化学方程式为CH4 (g)+3/2O₂(g)＝CO(g)+2H₂O（l）ΔH=－607 kJ·mol^-1。设不完全燃烧、完全燃烧的CH₄的物质的量分别是x、y，则x＋y="1" mol、607·x ＋802·y＝819.25 kJ

解得x="0.25" mol、y="0.75" mol

则消耗氧气的质量是（0.25×1.5＋0.75×2）mol×32g/mol＝60g，答案选C。

点评：该题是中等难度的试题，试题注重基础、灵活性强。主要是考查学生灵活运用基础知识解决实际问题的能力，有利于培养学生的逻辑推理能力。

完形填空

I started learning to play pipa at the age of four. At that time,I was really 1 of pipa because the four strings always cut my fingers. The cuts were not deep 2 they were long, and they really hurt ! So my parents bought me a roll of tape to protect the 3 of my left hand.After a few days, however, I 4 the tape! When my mother found out the reason, she said 5 and bought a new roll of tape.I had only used the second roll for a few weeks 6 I lost it again! "You should try to play pipa without tape," my father said to me. But I cried and 7 another roll. My father agree and bought me another new roll.After a few months, I lost the third roll! Then the 8 , and then the fifth After this happened eight times, my mother got really 9 !"I won't buy you any more tape," she said to me. " Now you have to play pipa without tape

You must 10 it is carelessness that hurts your fingers!"

小题1:A. fond B. afraid C. proud

小题2:A. but B. and C. then

小题3:A. arms B. ears C. fingers

小题4:A. sold B. lost C. bought

小题5:A. nothing B. anything C. something

小题6:A. until B. after C. before

小题7:A. asked for B. worried about C. thought of

小题8:A. third B. fourth C. fifth

小题9:A. happy B. excited C. angry

小题10:A. expect B. forget C. remember

单项选择题

公共财政管理在政府管理中具有( )地位。

A．重要

B．主要

C．辅助

D．核心