## anonymous one year ago A sample of gas occupies a volume of 55.5 mL. As it expands, it does 140.6 J of work on its surroundings at a constant pressure of 783 torr. What is the final volume of the gas?

1. Photon336

$pV = nRT$ pressure is constant. we need to figure out the definition of work $work = -pdV$ $-p \int\limits_{vi}^{vf} dv = -p(v_{f}-v_{i})$ $-p(V_{f}-V_{i} = work$ Work is done on the surroundings so it's negative $-140.6J = -p(V_{f}-V_{I})$ we know the initial volume so we re-arrange to find the final volume. J = joules. $\frac{ work }{ pressure } = \frac{ J }{ p } + V_{i}$ 1.03 atm = 784 torr plug everything in $\frac{ 140.6J }{ 1.03atm } +55mL =1.91 L$ @woodward @empty please check my math i'm bad at this stuff lol

2. Photon336

@Zale101 did I do this right?

3. anonymous

nope

4. Photon336

wait, I dont think it's negative pdV it's just pdV that would change the answer. 1. $W = p(V_{f}-V_{i})$ 2. $\frac{ W }{ -p } + V_{i} = V_{f}$ 3. My assumption was that work was done on the surroundings so Work was negative. 4. Which lead me to believe that the negatives canceled leaving us with$\frac{ -W }{ p } + V_{i} = V_{f}$

5. Photon336

@aaronq

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