This worked example problem demonstrates how to calculate the final temperature of a substance when given the amount of energy used, the mass and initial temperature. Problem:
300 grams of ethanol at 10 °C is heated with 14640 Joules of energy. What is the final temperature of the ethanol?
The specific heat of ethanol is 2.44 J/g·°C.
Use the formula
q = mcΔT
q = heat energy
m = mass
c = specific heat
ΔT = change in temperature
14640 J = (300 g)(2.44 J/g·°C)ΔT
Solve for ΔT:
ΔT = 14640 J/(300 g)(2.44 J/g·°C)
ΔT = 20 °C
ΔT = Tfinal - Tinitial
Tfinal = Tinital + ΔT
Tfinal = 10 °C + 20 °C
Tfinal = 30 °C
The final temperature of the ethanol is 30 °C.