Simple Chemistry(Gas Law) problem

[tabishis]

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Here's the problem I just solved and got 0.052 moles as my answer which is one of the answer choices but I am not too sure if I did it the right way:

A gas occupies 22.4 L at STP and 29.0 L at 100 celsius and 1 atm pressure. How many moles of gas did the system gain or lose?

I used following PV=nRT relation:

P1V1 P2V2
----- = -----
n1T1 n2T2

Where n2 is what I calculated at 0.947 moles and subtracted it from 1 mole which gave me 0.052 moles.

Any tips or clues would be appreciated. Thanks.

 

[RogueUnicorn]

looks right

 

[tabishis]

Thanks, Bleargh. Can anyone else confirm this, please?

 

[McEMCDB]

Yup, it's correct. I'll go over what I did so you can check the steps.

pV=nRT

(1atm)(22.4L)=n(0.082 L*atm*K−1*mol−1)(273K)

n = (1atm)(22.4L) / (0.082 L*atm*K−1*mol−1)(273K)

n=0.9998 ~= 1.000 mol

P1V1 P2V2
----- = -----
n1T1 n2T2

n2= (P2)(V2)(n1)(T1)/(T2)(P1)(V1)

n2 = (1atm*22.9L*1.000mol*273K)/(373K*1atm*22.4L) = 0.948 moles

(or you could just use n2=(P2*V2)/(R*T2))

1.000 - 0.948 = .052 moles (lost)

 

[tabishis]

Thanks, folks! 🙂