(d) For a reversible isothermal process, write an expression for ΔE in terms of q and w and an expression for ΔS in terms of q and T.

Video transcript

Welcome back everyone in this example. We need to determine which of the following equations is the correct expression for change in energy in terms of heat and work and change in entropy in terms of heat and temperature for a reversible ice, a thermal process. When we have an ice, a thermal process, we want to recall that we have constant temperature and we want to recall that specifically for an ice, a thermal process. We have our change in entropy equal to the heat that would be transferred which is represented by Q rev sub rev and is divided by the absolute temperature. Next we want to recall that for a reversible process, we have the production of the maximum amount of work produced and so we have work equal to maximum work based on the fact that we did say this is an ice, a thermal process and a reversible process, we can say that heat is equal to the heat that is transferred Q rev. And that based on our first law of thermodynamics, we're going to recall that the change in energy is thus equal to heat plus work where Q. Is our heat that is transferred by our system. Our system being the reaction and work is going to be the work done by our reaction or our ice a thermal process in this case. So this reaction here or equation here is going to be our first answer as the correct expression of change in energy in terms of heat and work and then for our change in entropy in terms of heat and temperature, we would say that our change in entropy is equal to heat transferred Q. Divided by absolute temperature. And this would be our second final answer as the second correct expression for change in entropy. And then our first expression we wrote out was for change in energy, both for reversible ice. A thermal process. I hope everything I reviewed was clear. If you have any questions, please leave them down below and I'll see everyone in the next practice video.