If 24g of ice at -5C is added to a isolated dewar containing 50 mL of water at 10C. What would the temperature of the system be at equilibrium if the heat capacity can be ignored and the system is completely isolated.
sp ht H2O (l) - 4.18 J/(gC)
sp ht H2O(s) = 2.01 J/(gC)
dHfus = 6.01 kJ/mol
Density H2O = 1g/ml
The Attempt at a Solution
I wasn't sure if the water would start to freeze or the ice would melt or if that is necessary to know. I approached the problem with the assumption that the ice melts and also that the transfer of heat from water to ice during melting is equal and opposite the heat transfer out of the surrounding and thus the terms cancel (I don't know if I can make this assumption). With that in mind
qrxn = -qsurr
qrxn = 24 *2.01 *(0 - (-5)) + 24*4.18*(Tf-0)
-qsurr = -50*4.18*(Tf-10)
Solving for Tf = 5.98C
My main question is if my assumptions are valid and also how would I know without it being said if the ice if going to melt of the water is going to freeze, or does it make a difference?