8. They have cut the ____ of their products by almost 30 per cent
A. prize B. price C. award D. reward
7. By the end of the century, France had made ____ with Britain.
A. choice B. peace C. use D. decision
6. He tries to keep his professional life completely ____ from his private life.
A. separate B. unforgettable C. similar D. normal
5. ____ is a system or method for carrying passengers or goods from one place to another.
A. destination B. transportation C. vacation D. explanation
4. They believe that all work is of ____ value.
A. tidy B. native C. global D. equal
3. I have an office that I ____ with some other teachers.
A. lie B. share C. spare D. spread
2. ____ is a tool with a heavy metal part on a long handle, used for hitting nails into wood.
A. rope B. saw C. hammer D. compass
1. Today we remember the ____ who died in the last war.
A. brave B. honest C. smart D. handsome
19.(共12分) 在某温度下,将H2和I2各0.10mol 的气态混合物充入10L的密闭容器中,充分反应,达到平衡后,测得 c(H2)= 0.0080mol/L
⑴求该反应的平衡常数。▲(要有解题过程)
⑵在上述温度下,该容器中若通入H2和I2各0.20mol 的气态混合物,试求达到化学平衡状态时各物质的浓度。▲(要有解题过程)
113.5kJ的热量,试写出甲醇燃烧的热化学方程式: ▲ 。
⑵ 已知:Na2O2(s)+CO2(g)=Na2CO3(s)+1/2O2(g)ΔH=-226kJ/mol 则反应2Na2O2(s)+2CO2(s)=2Na2CO3(s)+O2(g ) ΔH ▲ -452kJ/mol(填“>”、“<”、“=”)
⑶由气态基态原子形成1mol化学键释放的最低能量叫键能。从化学键的角度分析,化学反应的过程就是反应物的化学键的破坏和生成物的化学键的形成过程。在化学反应过程中,拆开化学键需要消耗能量,形成化学键又会释放能量。
化学键 |
H-H |
N-H |
N≡N |
键能/kJ·mol-1 |
436 |
391 |
945 |
已知反应N2(g)+3H2(g)2NH3(g) △H=a kJ·mol-1。试根据表中所列键能数据估算a 的数值:___▲___。
⑷ 依据盖斯定律可以对某些难以通过实验直接测定的化学反应的焓变进行推算。
已知:C(s,石墨)+O2(g)=CO2(g) △H1=-393.5kJ·mol-1
2H2(g)+O2(g)=2H2O(l) △H2=-571.6kJ·mol-1
2C2H2(g)+5O2(g)=4CO2(g)+2H2O(l) △H3=-2599kJ·mol-1
根据盖斯定律,计算298K时由C(s,石墨)和H2(g)生成1mol C2H2(g)反应的焓变:__▲_。
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