here, we're going to say that the heat of combustion is the amount of heat released when a mole of a substance is burned or combusted. Now recall the combustion reaction normally involves a compound with carbon and hydrogen or carbon, hydrogen and oxygen reacting with 02 Of course, there are other elements that could be involved such a sulfur or nitrogen. But the most common types of combustion reactions are just carbon and hydrogen or carbon, hydrogen and oxygen. Now we're gonna say associated with any combustion reaction is a heat of combustion value, which we represent as Delta H Not so that little circle combustion so well, abbreviate it as comb. So just remember, when discussing constant value volume telemetry, we associated with a combustion reaction.