- #1

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I tried finding the pressure at 30°C assuming volume stays the same using P1/T1=P2/T2 and got nowhere after that. Then I tried setting P to be equal and use the resulting formula of T1/V1=T2/V2 and got a percentage greater than 100%...

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- Thread starter physicsss
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- #1

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I tried finding the pressure at 30°C assuming volume stays the same using P1/T1=P2/T2 and got nowhere after that. Then I tried setting P to be equal and use the resulting formula of T1/V1=T2/V2 and got a percentage greater than 100%...

- #2

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Now keep the temperature constant and express the volume at initial pressure as a sum of initial volume and some increment. Now it is simple arithmetic.

- #3

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I don't understand why you keep the temperature constant...can you explain some more?

- #4

lurflurf

Homework Helper

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So we havephysicsss said:

I tried finding the pressure at 30°C assuming volume stays the same using P1/T1=P2/T2 and got nowhere after that. Then I tried setting P to be equal and use the resulting formula of T1/V1=T2/V2 and got a percentage greater than 100%...

n1T1=n2T2

so

n2/n1=T1/T2

n= amount of substance

T= temperature (absolute)

T1=(273.15+10)k=283.15k

T2=(273.15+30)k=303.15k

we desire to find

(n1-n2)/n1=1-n2/n1

fraction of air removed=1-n2/n1=1-T1/T2=1-(283.15k)/(303.15k)=6.6%

The general form for the ideal gas assumption for two sets of conditions is

(P1V1)/(n1T1)=(P2V2)/(n2T2)

P=pressure (absolute)

V=volume

n= amount of substance

T= temperature (absolute)

any that do not change may be droped

here pressure and volume we constant giving

n1T1=n2T2

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