Whats the difference between enthalpy and molar heat of combustion? (1 Viewer)

[tycho]

Whats the difference between enthalpy and molar heat of combustion? How do you work each one out?

 

[gigglinJess]

Enthalpy
Enthalpy is the heat content of a substance/group of substances.

Change in enthalpy
ΔH = heat absorbed per mole when the reaction occurs at a specific pressure

ΔH = enthalpy of products - enthalpy of reactants

Endothermic reactions : ΔH is positive
Exothermic reactions : ΔH is negative

Molar heat of combustion
The amount of heat released per unit mass or unit volume of a substance when the substance is completely burned
ΔH = -mcΔT

where m = mass of water heated
c = specific heat of water (4.18 x 10^3 J kg^-1 K^-1)
ΔT = change in temperature (final temp - intitial temp)

Hope this helps you