science
posted by Justin .
as 390 g of hot milk cools in a mug, it transfers 30,000 J of heat to the environment. What is the temperature change of milk? The specific heat of milk is 3.9 J/g degree C.

recall that heat absorbed released is given by
Q = mc*(T2  T1)
where
m = mass (in g)
c = specific heat capacity (in J/gk)
T = temperature (in C or K)
*note: Q is (+) when heat is absorbed and () when heat is released.
we're looking for (T2  T1) here. substituting,
30000 = 390*3.9*(T2  T1)
(T2T1) = 19.72 K
hope this helps~ :)