Heat of Combustion Calculator

Your details

Calorimetry uses bomb/coffee-cup calorimeter readings. Formation enthalpies uses standard thermodynamic tables.
Choose a common fuel for pre-filled standard values, or choose Custom to enter your own.
Mass of water (or solution) absorbing the heat in the calorimeter.
g
Standard specific heat capacity of liquid water. Change only if using a different solvent.
J/(g·°C)
Temperature increase of the water (T_final minus T_initial).
°C
Mass of fuel consumed during combustion (measured by weighing before and after).
g
Molecular weight of the fuel. Used to convert energy per gram to energy per mole.
g/mol
Choose the unit for the primary result. All three values are always shown in the outputs.
Optional: enter moles of fuel to calculate total energy released for that quantity.
mol
Heat of combustionLow energy density
159.4kJ/mol

Molar heat of combustion (exothermic magnitude, positive convention)

Heat of combustion per gram9.937kJ/g
Heating value9.94MJ/kg
Total energy released159.4kJ
Heat absorbed by calorimeter (Q)7.95kJ
Moles of fuel burned0.04988mol
Reaction enthalpy (signed)-159.4kJ/mol
kJ/mol159.4
kJ/g9.937
MJ/kg9.94

Heat of combustion: 159.4 kJ/mol (9.94 MJ/kg)

  • The heat of combustion is 159.4 kJ/mol, meaning that amount of energy is released as heat for every mole of fuel completely burned.
  • Expressed as a heating value, that is 9.94 MJ/kg - useful for comparing fuels by weight.
  • For 1 mol of fuel, the total energy released is 159.4 kJ.
  • The tabulated standard value for this fuel is 890 kJ/mol. Your experimental result is 82.1% below that reference.

Next stepCompare your result against the tabulated standard value below. Common sources of error include incomplete combustion, heat loss to surroundings, and inaccurate mass measurement.

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