The temperature of a sample of iron with a mass of 20.0 grams changed from 60.0ºC to 35.0ºC. How many Joules of heat were released?

This can be calculated using the equation q = mcΔT where m is the mass of iron, c is its specific heat capacity and Δ T is the change in temperature.

Assuming c does not change with temperature and has a value of:

c = 0.444 J/K mol, the q can be calculated as:

q = 20.0 g * 0.444 J/K mol * 25 K = 222 J

(Note: K refers to Kelvin which equals ˚C + 273, therefore Δ T is the same in K as it is in ˚C.)