when to use each equation


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Eunice Lee 1A
Posts: 60
Joined: Wed Oct 03, 2018 12:16 am

when to use each equation

Postby Eunice Lee 1A » Sat Feb 09, 2019 9:55 am

When do you use w = -Pex(deltaV) vs. w = -nRTln(V2/V1)?

Nicole Elhosni 2I
Posts: 62
Joined: Fri Sep 28, 2018 12:28 am

Re: when to use each equation

Postby Nicole Elhosni 2I » Sat Feb 09, 2019 10:18 am

When pressure is constant (in an irreversible expansion), you will use the first equation w=-pΔV.
When pressure is not constant (in a reversible expansion), you will use the second equation w=-nRTln(V2/V1)

JadeSebti1L
Posts: 35
Joined: Fri Sep 28, 2018 12:19 am

Re: when to use each equation

Postby JadeSebti1L » Sat Feb 09, 2019 10:35 am

An easy way to remember it is that whatever variable is constant is included in the equation.
CONSTANT P: w = -Pex(deltaV)
CONSTANT T: w = -nRTln(V2/V1)?


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