The laws of thermodynamics

[@Whoeveriam226]

8:10 it also holds for irreversible processes

[@nomachinesinthisroom]

Hello! Thank you for the videos! Just a question: isn't the 1st law defined as the change in a system’s energy during a thermodynamic process equaling the heat added to the system, minus the work it performs on its environment? In this case it would be dE=dQ-dW. Is there something I'm not seeing? Thank you!

[@kumaneko50732]

Sometimes the first law is written in terms of work done *on* the system (by the surroundings), and other times in terms of the work done *by* the system (on the surroundings). It should be clear that one of these conventions has the opposite sign of the other in the equations. What you wrote is correct because you are considering work done by the system, but the statement in the video is also correct as it considers the amount of work done on the system. You can read a little more about this on wikipedia: en.wikipedia.org/wiki/First_law_of_thermodynamics#Sign_conventions

[@nomachinesinthisroom]

@@kumaneko50732 I see what you mean! Thank you!