✔ 最佳答案
Molecules of solid are held very tightly together. Usually, when no.of moles(amount)↑/↓, volume follows to ↑/↓ proportionally, therefore, concentration is fixed.
Molecules of gas are loosely held together. ↑/↓ of moles of gas cannot ↑/↓ volume of the system.
2011-12-23 13:07:59 補充：
Therefore, with fixed volume and in fact, ↑/↓ no. of moles of gas -> ↑/↓ concentration of the system.
2011-12-23 15:17:33 補充：
no, i mean the solid and liquid molecules are forced to hold together.
but gas cannot and they will collide to each other at high speed in the system.
if the system is said to be an atmosphere, the volume cannot be determined since the gas molecules are not fixed and held to each other.
2011-12-23 15:19:24 補充：
if the system is in container(closed system), gas molecules cannot escape from the system. And the volume is usually fixed because increasing the amount of gas molecules cannot increase the volume of the system, but can increase the concentration.
2011-12-23 15:21:01 補充：
moreover, to maintain an equilibrium, the system should be closed if it involves gases, because gas molecules will escape, and the volume will be fixed, ↑/↓ no. of moles of gas -> ↑/↓ concentration.
2011-12-23 15:22:15 補充：
while solid and liquid cannot escape, and since the molecules/compound of solid/liquid are usually packed closely together, and again, as mentioned b4, when no.of moles(amount)↑/↓, volume follows to ↑/↓ proportionally, therefore, concentration is fixed.
2011-12-23 15:25:44 補充：
you should be able to identify the keywords no.of moles, volume and concentration, the relationship is quite complicated.
2011-12-25 16:56:04 補充：
The answer is as follows:
To maintain an equilibrium, thesystem should be closed if it involves gases, because gas molecules willescape, and the volume will be fixed, ↑/↓ no. of moles of gas -> ↑/↓concentration.On the other hand, while solid and liquid cannot escape, andsince the molecules/compound of solid/liquid are usually packed closelytogether, and again, as mentioned in the opinion area, when no.of moles(amount)↑/↓, volumefollows to ↑/↓ proportionally, therefore, concentration is fixed.
2011-12-25 16:57:52 補充：
because i didnt expect to answer this question, just wanna give opinions (at the beginning i hv no idea about the question) ... but finally the answers are still given my me lol...
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