The discussion revolves around a thermodynamics problem involving a cherry pie's heat transfer and entropy change. The original poster seeks to determine the final temperature of the pie after it absorbs a specified amount of heat, given its initial temperature and the increase in entropy.
Several participants have offered guidance on how to approach the problem, emphasizing the importance of understanding the equations related to heat and entropy. There is recognition of the need to analyze the problem without providing direct solutions, and some participants reflect on their own initial misunderstandings.
Participants note that the problem does not provide the temperature of the surroundings, which could influence the heat transfer calculations. There is also a mention of the need to assume constant heat capacity for the cherry pie.
Sorry, but you have to try something. Do you know the equation for how the heat that enters is related to the temperature rise? Do you know the equation for how the entropy change is related to the initial and final temperatures. Both these equations involve the heat capacity.suchjoe said:Homework Statement
When 1.70 ✕ 105 J of heat enters a cherry pie initially at 20.0°C, its entropy increases by 470 J/K. What is its final temperature?
Homework Equations
The Attempt at a Solution
I have no clue
suchjoe said:Homework Statement
When 1.70 ✕ 105 J of heat enters a cherry pie initially at 20.0°C, its entropy increases by 470 J/K. What is its final temperature?
Homework Equations
The Attempt at a Solution
I have no clue
Something like the last equation is the one to use, but I'm sure they want you to assume that the heat capacity is constant. You don't need to know the surroundings temperature, so don't waste your time looking for that.wreckemtech said:Generally, S = Q/T. Kind of simplistic, but that is probably what you're going to use to find the net heat transfer into the cherry pie. Then, you'll need to know the heat capacity of the cherry pie to determine the change in temperature. Does the problem statement give the temperature of the surroundings? If so, I'd use that as the temp at which the heat transfer occurs. And if this is a college thermo class, dS = Cavg*ln(t2/t1)
According to PF rules, we really shouldn't be doing the problem for suchjoe. We should just be giving him little hints so that he can analyze it for himself. I feel like I've already revealed too much about how to do it.wreckemtech said:You know, I somehow completely missed the fact that Q was given in the problem statement. I thought the poster was only given T1 and dS. If Q is known, it should be easy enough to substitute something like Q=C(T2-T1) into the first equation, and then C will cancel.
wreckemtech said:Sorry. I'm new here.