An iron bar of mass 869 g cools from 94 C to 5 C. Calculate the heat releases in (Kilojoules) by the metal.

For this question, we apply the equation:

Q = mCp ΔT

Where m is the mass of the substance, Cp is its specific heat capacity and ΔT is the temperature change.

Q = 896 x 0.45 x (5 - 94)

Q = - 35884.8 Joules

So about - 36 kilojoules of heat is released.