There are 2 very different reactions that involve heat. There are endothermic reactions as well as exothermic reactions that involve heat.
an exothermic reaction is when two chemical react with each other and give out heat (the temperature increases). This is because bonds have to be broken and this involves extra energy being released, this energy is released as heat
endothermic reaction a positive enthalpy.
This the heat released during a chemical reaction.
If you wanted to, you could ask what the heat of formation is of a given compound such as diphosphorus pentasulfide, but if you want to know about a heat of reaction, you have to specify a reaction. A compound is not a reaction.
Exothermic reaction: with release of heat Endothermic reaction: with absorption of heat
A combustion reaction involves the three reactants from the fire triangle, heat, oxygen, and fuel.
fusion
combustion
an exothermic reaction is when two chemical react with each other and give out heat (the temperature increases). This is because bonds have to be broken and this involves extra energy being released, this energy is released as heat
Heat of a reacion is the totall amount of heat a reaction produces. Molar heat of a reaction is the heat produced/mol if you have the molar hear of the reaction you can calculate the heat of the reaction based on the moles of reactants you have
an acid-base titration reaction involves a neutralization reaction.
An exothermic reaction involves the release of heat into a system. The burning of a candle is combustion reaction. Combustion reaction release heat, and this can be detected and measured by the burning of a candle's wax. From these testable observations it is determined fact that candle burning is indeed exothermic.
If heat from a reaction is released, it is an exothermic reaction.
An endothermic reaction absorbs heat, an exothermic reaction releases heat.
Chemical reaction involves breaking of old links and forming new links. As the energy needed to break and form is different, there is an energy change, some major part of it is heat, so the chance of autothermicity is really small
endothermic reaction a positive enthalpy.
Heat is released during an exothermic reaction.