What is the calorimetry formula?

q = m × c × ΔT, where q is heat in joules, m is mass in grams, c is specific heat capacity in J/(g·°C), and ΔT is the change in temperature.

What is the specific heat of water?

About 4.18 J/(g·°C). This is much higher than most substances, which is why water is so effective for absorbing or releasing heat.

Is q positive or negative?

Positive when heat is absorbed (endothermic), negative when heat is released (exothermic). The sign of ΔT tells you which: warming = positive q for the system absorbing heat.

How does this relate to ΔH?

In a coffee-cup calorimeter at constant pressure, q = ΔH for the reaction. The molar enthalpy change ΔH = q / n, where n is the moles reacted.

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NSW · HSCChemistry

Calorimetry calculator

q = mcΔT, solve for any variable. Default c is water (4.18 J/(g·°C)).

Inputs

Solve forMass m (g)Specific heat c (J/(g·°C))Water = 4.18Temperature change ΔT (°C)Heat q (J)

Result

Heat q

4180J

q = m × c × ΔT. Positive q means heat absorbed; negative means heat released.

How this calculator works

It rearranges q = m × c × ΔT for whichever variable is unknown. Use grams and Celsius and you will get joules. For water, c = 4.18 J/(g·°C); for other substances, look up the specific heat capacity.

Common questions

What is the calorimetry formula?: q = m × c × ΔT, where q is heat in joules, m is mass in grams, c is specific heat capacity in J/(g·°C), and ΔT is the change in temperature.
What is the specific heat of water?: About 4.18 J/(g·°C). This is much higher than most substances, which is why water is so effective for absorbing or releasing heat.
Is q positive or negative?: Positive when heat is absorbed (endothermic), negative when heat is released (exothermic). The sign of ΔT tells you which: warming = positive q for the system absorbing heat.
How does this relate to ΔH?: In a coffee-cup calorimeter at constant pressure, q = ΔH for the reaction. The molar enthalpy change ΔH = q / n, where n is the moles reacted.