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Topic: ideal gas equation?  (Read 10048 times)

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polaris

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ideal gas equation?
« on: December 27, 2005, 08:10:54 PM »
which of the following is impossible for an ideal gas?

a) V1/T1=V2/T2
b) V1T1=V2T2
c) V1/V2=T1/T2
d) V2=(T2/T1)V1

im not even sure how to begin this problem...all i know is that PV=nRT... :'(    i tried the problem and i think the answer is b...but can someone explain to me specifically?
« Last Edit: December 27, 2005, 08:31:26 PM by polaris »

Offline buckminsterfullerene

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Re:ideal gas equation?
« Reply #1 on: December 27, 2005, 10:09:07 PM »
you are not paying attention to the pressure or the number of moles in the solution, so you do not need the R constant either, so generally what you do know is the volume and the temperature.
PV=nRT
V1=T1
-what this says is that you are observing the volume and temperature through the entire experiment, so you also need to have an equation for the end.
V2=T2
we try to set a value that is equation on both equation such as,
V1/T1=1   -and-    1=V2/T2
to get that you only needed to divide T and T divided by itself is 1, but now we have that both equations are equal to one and we could say that:
V1/T1=V2/T2
which is the same as choice (a), but that is how the equation is set up before solving a problem, just explained step by step, does not really need all these calculations you are simply supposed to learn them subconciously, now to say what would the answer be b and not c or d well we are trying to solve for an unknown value.  lets say that they give you the volume for the beginning and the temperature, if they give the volume or the temperature when the solution goes to completion you could arrange the problem algebraically so that you could solve for the equation, just set it equal to the value that you are not given and then substitute.
by multiplying both sides by the denominator of each side of the equation you get that
V1V2=T1T2
well you can say that it cannot be
V1V1=T2T2
and there is your answer explained specifically :Lighten:
currently a student attending high school in South Florida, capital of all the hurricanes that come through the US, and the sunshine state.  My interests falls into electrochemistry going to renewable resources of energy, i like hydrogen fuel cells and solar energy

polaris

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Re:ideal gas equation?
« Reply #2 on: December 27, 2005, 10:29:19 PM »
im sorry...but i still don't fully understand what you mean...

QUOTE:

by multiplying both sides by the denominator of each side of the equation you get that
V1V2=T1T2
well you can say that it cannot be
V1V1=T2T2

does that mean it is or it isn't choice b?

Offline Donaldson Tan

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Re:ideal gas equation?
« Reply #3 on: December 29, 2005, 12:07:06 AM »
PV = nRT
=> V/T = nR/P
=> V/T = constant at constant pressure and fixed mass

V1 / T1 =  V2 / T2 = constant
« Last Edit: December 29, 2005, 12:07:31 AM by geodome »
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