Calculating Work

[Eileen Si 1G]

When would you know to use w=-P*delta V versus w=-nRTln(V2/V1) to calculate work of expansion? (Like in homework 4A.5)

[Justin Sarquiz 2F]

Lavelle has not gone over this topic yet because he is starting on thermochemistry first and then going to thermodynamics. I am guessing that you would use the equation according to the information given in the problem.

[Sean Cheah 1E]

Use the first equation for irreversible expansions/contractions occurring against constant external pressure. Use the second equation for reversible expansions where the external pressure is always equal to the internal pressure (pressure of the expanding/contracting gas).