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Old Sep 2nd 2008, 09:29 PM   #1
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I saw a p-T graph which has a constant positive slope. Here is a statement:

~The gas volume V is increasing.

From the equation pV=nRT,
Slope of the p-T graph should represent a constant over volume. With the mass fixed and a constant positive, I don't see why the statement is said to be correct judging from the graph?
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Old Sep 3rd 2008, 02:54 PM   #2
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Originally Posted by werehk View Post
I saw a p-T graph which has a constant positive slope. Here is a statement:

~The gas volume V is increasing.

From the equation pV=nRT,
Slope of the p-T graph should represent a constant over volume. With the mass fixed and a constant positive, I don't see why the statement is said to be correct judging from the graph?
I we know that V is increasing then the Ideal Gas Law does not predict a straight line for the T vs. p graph. So if the graph is a straight line, then V cannot be increasing.

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Old Sep 8th 2008, 07:39 AM   #3
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I overlook that temperature is in celcius scale. My classmates explained that when T is 0, P/T tends to infinity. When T increases, P/T drops. As PV/T is a constant, V must be increasing.

I guess myself would never figure out such kind of logical relationship.....
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