An insulated Thermos contains 127 cm3 of hot coffee at 79°. You put a 12.0 g ice cube at its melting point to cool the coffee. By how many degrees has your coffee cooled once the ice has melted and equilibrium is reached? Treat the coffee as though it were pure water and neglect energy exchanges with the environment.
The Attempt at a Solution
Qtotal=Qwater+Qice melting+Qice warming=0
(0.012kg)(333x10^3 J/kg) + (0.012kg)(4180 J/(kg*k))(Tf-273K)+(0.127kg)(4180 J/(kg*K))(Tf-352)=0
Tf=338.303K or 65.302 C
Any help would be appreciated. I have no idea where I am going wrong with this one.