How to Calculate a Final Temperature

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When you have a chemistry or physics problem which asks you to calculate the final temperature of a substance, for example, you apply a certain amount of heat to water at a particular beginning temperature, you can find the answer using one of the most common thermodynamics equations. Straddling the boundary between chemistry and physics, thermodynamics is a branch of physical science with deals with transfers of heat and energy in nature, and the universe as a whole.

    Rewrite the specific-heat equation, Q=mcΔT. The letter "Q" is the heat transferred in an exchange in calories, "m" is the mass of the substance being heated in grams, "c" is its specific heat capacity and the static value, and "ΔT" is its change in temperature in degrees Celsius to reflect the change in temperature. Using the laws of arithmetic, divide both sides of the equation by "mc" as follows: Q/mc = mcΔT/mc, or Q/mc = ΔT.

    Plug the values your chemistry problem gives you into the equation. If, for example, it tells you that someone applies 150 calories of heat to 25.0 grams of water, whose specific heat capacity, or the amount of heat it can withstand without experiencing a change in temperature, is 1.0 calories per gram per degree Celsius, populate your equation as follows: ΔT = Q/mc = 150/(25)(1) = 150/25 = 6. Therefore, your water increases in temperature by 6 degrees Celsius.

    Add the change in temperature to your substance's original temperature to find its final heat. For example, if your water was initially at 24 degrees Celsius, its final temperature would be: 24 + 6, or 30 degrees Celsius.


About the Author

Robert Schrader is a writer, photographer, world traveler and creator of the award-winning blog Leave Your Daily Hell. When he's not out globetrotting, you can find him in beautiful Austin, TX, where he lives with his partner.