Heat Transfer Formula

Heat, a measure of thermal energy, can be transferred from one point to another. Heat flows from the point of higher temperature to one of lower temperature. The heat content, Q, of an object depends upon its specific heat, c, and its mass, m. The Heat Transfer is the measurement of the thermal energy transferred when an object having a defined specific heat and mass undergoes a defined temperature change.

Q = mcΔT

Q = heat content in Joules

m = mass

c = specific heat, J/g °C

T = temperature

ΔT = change in temperature

Heat Transfer Formula Questions:

1) How much energy is transferred if a block of copper with a mass of 50 g is heated from 20°C to 100 °C? The specific heat of copper, Cu, is c = 0.386 J/g°C.

Answer: The temperature change Δ T = 100 °C - 20 °C = 80 °C. The mass, m = 50 g. Use the formula for Heat Transfer.

Q = mcΔT

Q = (50 g)(0.386 J/g°C)(80 J/g°C)

Q = 1544 Joules

2) The specific heat for aluminum is c = 0.900 J/g°C. What mass of aluminum is required to cause a heat transfer of 1500 Joules if the temperature change is 33 °C?

Answer: The change in temperature, ΔT = 33°C, and the specific heat for aluminum, c = 0.900 J/g°C. The heat transfer Q = 1500 Joules.

Q = mcΔT

m = Q/(cΔT)

m = 1500 Joules/(0.900J/g°C)(33°C)

m = 1500 Joules/(29.7J/g)

m = 50.51 g