What is the equation for heat energy change?

• A. Q = mcΔT
• B. Q = m ΔT c
• C. Q = c m ΔT^0
• D. Q = m c ΔT^2

Answer: (A)

Heat energy change depends on three things: how much material you have, how much energy that material stores per degree of temperature change, and how big that temperature change is. The amount of heat (Q) you need or remove is calculated by multiplying mass (m), the specific heat capacity (c), and the change in temperature (ΔT): Q = m c ΔT. Specific heat capacity tells you how many joules are needed to raise the temperature of 1 kilogram by 1 kelvin, so multiplying by mass and by the temperature change gives the total energy involved. ΔT is the difference between final and initial temperature, measured in kelvin (or °C for a change). The heat depends linearly on ΔT, not on ΔT squared, so a form with ΔT^2 would misrepresent how heat changes with temperature. Hence, Q = mcΔT is the correct expression.