Physics, almost have it!
posted by Tia on .
In a physics lab experiment, a student immersed 205 onecent coins (each having a mass of 3.00 g *.003kg) in boiling water. After they reached thermal equilibrium, she quickly fished them out and dropped them into 0.244 kg of water at 20.0 C in an insulated container of negligible mass.
What was the final temperature of the coins? [Onecent coins are made of a metal alloy  mostly zinc  with a specific heat capacity of 390 J/(kg*K).]
I know that:
Mass,coins=.615 kg
Mass,water=.244 kg
c,coin=390 J/(kg*K)
c,water=418.6 J/(kg*K)
Ti, coins= 100C, 373.15K
Ti, water= 20C, 293.15K
The problem asks for the Tf of the coins, but I'm still missing the Tf of the water...I'm thinking it has something to do with the equilibrium point, but I dont' know that that is!
Heat lost by the coins + heat gained by the water = 0
mass x specific heat x (Tf  Ti) + mass x specific heat x (Tf  Ti) = 0

answered in a duplicate post above.