Good catch.mjc123 said:
The first principle of thermodynamics, also known as the law of conservation of energy, states that energy cannot be created or destroyed, only transferred or converted from one form to another.
In chemical reactions, the first principle of thermodynamics means that the total energy of the reactants must be equal to the total energy of the products. This is known as the principle of energy conservation.
Heat refers to the transfer of energy from a hotter object to a cooler object, while temperature is a measure of the average kinetic energy of the particles in a substance. The first principle of thermodynamics deals with the total energy of a system, including both heat and other forms of energy.
Enthalpy is a measure of the total heat content of a system. The first principle of thermodynamics states that the change in enthalpy in a chemical reaction must be equal to the heat exchanged between the system and its surroundings, assuming constant pressure.
An example of the first principle of thermodynamics in action is a combustion reaction, where the chemical energy stored in the reactants is converted into heat and other forms of energy. The total energy of the reactants is equal to the total energy of the products, in accordance with the first principle of thermodynamics.