Science question

Question

whats the answer to on a winter day the temperature drops -5 Celsius to -15 Celsius overnite if a pan sitting outside contains 0.40kg of ice how much heat is removed from the ice for this temperature change

Answer 1

Since water freezes at 0ºC, the only thing to be concerned with here is the heat removed from the ice, and no phase change. To answer this question, one needs to know the specific heat of ice, which happens to be 2.09 J/g-deg (you can look this up in a book or a table). Then you use the equation that q = mC∆T where

q = heat =?

m = mass = 0.40 kg x 1000 g/kg = 400 g (changed to g to be consistent with units of C)

C = specific heat = 2.09 J/g-deg

∆T = change in temperature = 10ºC

q = (400 g)(2.09 J/g-deg)(10 deg) = 8360 J = 8.4 kJ = heat lost by the ice