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发表于 17-2-2008 12:36 AM
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帮忙顶。。。帮忙顶。。。
08年的考生都去了那里？？？
真怀念以前每天上来这里看问题的日子，
现在也好像回答，但是。。。
我忘了。。。
等我得空复习先 |
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发表于 17-2-2008 12:37 PM
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对咯，都不知道０８年的考生都到哪去了。可能是很努力地在拼了。 |
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发表于 17-3-2008 02:25 PM
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发表于 31-5-2008 03:30 PM
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我就是08年的考生...哈哈..但我不会回答耶...怎么办? |
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发表于 31-5-2008 03:42 PM
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顶下，很多问题可以在这里找到。 |
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发表于 31-5-2008 07:13 PM
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那怎么办??没有人回答........... |
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发表于 1-6-2008 12:52 AM
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发表于 1-6-2008 10:29 AM
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发表于 1-6-2008 08:06 PM
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Calculate the number of nitrogen atoms in a container of volume 0.50 dm^3 at 0 d.celcius . The pressure of the gas is 101 Nm^-2.
我的做法是（请大家帮忙批改下，谢谢）
Mole of nitrogen atom = 0.50 dm^3 / 22.4 dm^3 = 0.0223 mole
Number of nitrogen molecules = 0.0223 x 6 x 10^23 = 1.338 x 10^22
Number of nitrogen atoms = 1.338 x 10^22 x 2 = 2.676 x 10^22 |
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发表于 2-6-2008 12:02 AM
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原帖由 darksider 于 1-6-2008 08:06 PM 发表 
Calculate the number of nitrogen atoms in a container of volume 0.50 dm^3 at 0 d.celcius . The pressure of the gas is 101 Nm^-2.
我的做法是（请大家帮忙批改下，谢谢）
Mole of nitrogen atom = 0.50 ...
Can also be done by using the ideal gas law, PV=nRT |
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发表于 2-6-2008 12:50 AM
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原帖由 morphv02c01 于 2008/6/2 12:02 AM 发表 
Can also be done by using the ideal gas law, PV=nRT
I have used that formula to do too and got the same answer.
However, the answer in the answer key is 2.676 x 10^19 and I assume it's wrong after recalculating for various times. |
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发表于 2-6-2008 01:00 PM
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原帖由 darksider 于 2-6-2008 12:50 AM 发表
I have used that formula to do too and got the same answer.
However, the answer in the answer key is 2.676 x 10^19 and I assume it's wrong after recalculating for various times.
Suppose if the Q gives u the temp, pressure, volume, u should use the ideal gas law quation to calculate, otherwise u might not get the marks.
I calculated, and the ans given was correct, 2.679x10^19.
You forgot to convert the dm^3 given in the question to m^3 I suppose.. That's what that makes your answer wrong. Beware of the units used in the equation. 
[ 本帖最后由 morphv02c01 于 2-6-2008 01:03 PM 编辑 ] |
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发表于 2-6-2008 01:24 PM
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原帖由 morphv02c01 于 2008/6/2 01:00 PM 发表
Suppose if the Q gives u the temp, pressure, volume, u should use the ideal gas law quation to calculate, otherwise u might not get the marks.
I calculated, and the ans given was correct, 2.6 ...
Thanks for correcting me.
But why should I convert the dm^3 to m^3? Is it because of the pressure given is in Nm^-2? |
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发表于 2-6-2008 02:38 PM
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回复 633# darksider 的帖子
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是的，dimension和unit都必须一样，缺一不可 |
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发表于 2-6-2008 02:50 PM
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原帖由 hamilan911 于 2008/6/2 02:38 PM 发表
是的，dimension和unit都必须一样，缺一不可
谢谢 |
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发表于 10-6-2008 09:15 PM
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请问Ecell和E*cell有什么不同....他们要怎么找??
* 那个象数学ANGLE的那个SYMBOL....... |
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发表于 11-6-2008 02:09 AM
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原帖由 幸福蛋糕 于 10-6-2008 09:15 PM 发表
请问Ecell和E*cell有什么不同....他们要怎么找??
* 那个象数学ANGLE的那个SYMBOL.......
Ecell是electrode potential.
E*cell是standard electrode potential |
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发表于 11-6-2008 01:58 PM
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E*cell 就用formula而已， E*cell=E*cathode - E*anode (signs remain unchanged)
Ecell的话就用 Nernst quuation |
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发表于 11-6-2008 05:01 PM
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谢谢你们...
还有:
当一个SYSTEM已经EQUILIBRIUM了...但我加热.....他就会SHIFT TO ACHIEVE NEW EQUILIBRIUM 对吗??
那英文要怎样解释??
什么FAVOUR ENDOTHERMIC的...
很乱.. |
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发表于 11-6-2008 10:59 PM
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原帖由 幸福蛋糕 于 11-6-2008 05:01 PM 发表
谢谢你们...
还有:
当一个SYSTEM已经EQUILIBRIUM了...但我加热.....他就会SHIFT TO ACHIEVE NEW EQUILIBRIUM 对吗??
那英文要怎样解释??
什么FAVOUR ENDOTHERMIC的...
很乱..
endo &exothermic...
endothermic,delta H= positive的,会在加热时shift to right
&vice versa |
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