<p>"A sample of an ideal gas at 15.0 atm and 10.0 L is allowed to expand against a constant external pressure of 2.00 atm at a constant temperature. Calculate the work in units of kJ for the gas expansion. (Hint: Boyle's law applies)."</p>
<p>Alright, P1V1=P2V2 in Boyle's law, and P1 = 15 atm, V1 = 10 L, but how to find P2 and V2 and then, subsequently, complete the rest of the problem?</p>
<p>Find V2 using Boyles Law.</p>
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(source: <a href="http://en.wikipedia.org/wiki/Work_%28thermodynamics%29%5B/url%5D">http://en.wikipedia.org/wiki/Work_%28thermodynamics%29</a> )</p>
<p>You have change in volume, you have external pressure, find work.</p>
<p>EDIT: What? No hotlinking? Ah well, the equation is</p>
<p>W(done on system) = -(integral from Vi to Vf) P dv</p>
<p>(Note that this type of problem will not be on the AP exam.)</p>
<p>There have been one or two MC questions in the past where you were expected to calculate work. No integrals needed, however. Just a simple work(done by system)=-PdeltaV. The new volume can be found from Boyle's law - the gas will expand until internal pressure is equal to external pressure, so
P1V1=P2V2
15<em>10=2</em>V2
Once you found the new volume, substitue the change in volume and the external pressure into the work equation.</p>
<p>Note: Wxmann's integral formula is correct, but when external pressure is constant, it simplifies to
w(done by system)= -P(Vfinal-Vinitial)</p>
