2011-04-03, 03:30 AM
Since they already tell you the ice will be melt at then end, all you have to do is calculate how much energy you need to go from:
-9,3ºC to 0ºC as ice (ice heat capacity 37.5 J/K.mol times the temperature difference and total ammount of ice in mols)
Energy1 = (0 - (-9.3)) * (37.5) * (mols of ice)
-0ºC ice to 0ºC water (entalpy of fusion, 6.01*10³ J/mol times the ammount of ice in mols).
Energy2 = (mols of ice) * (6.01*10³)
Then you take these two ammounts of energy you used to heat the ice and you use it to calculate how much the water has cooled:
(Energy1 + Energy2) = (water heat capacity) * (Nº of mols of water) * (95.3º - NewTemperature)
After that, to the final temperature you just need to do a weighted average of the two bodies of water, the one at 0ºC and the one at the temperature you just calculated.
(mass of water at ºC) * (0ºC) + (mass of water at NewTemperature) * (NewTemperature) = (total mass of water) * (Final Temperature)
Also, take care for when the values of entalpy/heat capacity are in kJ or J. And be sure to use mols when the aforementioned are per mol.
-9,3ºC to 0ºC as ice (ice heat capacity 37.5 J/K.mol times the temperature difference and total ammount of ice in mols)
Energy1 = (0 - (-9.3)) * (37.5) * (mols of ice)
-0ºC ice to 0ºC water (entalpy of fusion, 6.01*10³ J/mol times the ammount of ice in mols).
Energy2 = (mols of ice) * (6.01*10³)
Then you take these two ammounts of energy you used to heat the ice and you use it to calculate how much the water has cooled:
(Energy1 + Energy2) = (water heat capacity) * (Nº of mols of water) * (95.3º - NewTemperature)
After that, to the final temperature you just need to do a weighted average of the two bodies of water, the one at 0ºC and the one at the temperature you just calculated.
(mass of water at ºC) * (0ºC) + (mass of water at NewTemperature) * (NewTemperature) = (total mass of water) * (Final Temperature)
Also, take care for when the values of entalpy/heat capacity are in kJ or J. And be sure to use mols when the aforementioned are per mol.

