Standard State: A reference state for specific substances during changes in their condition. For pure substances, the standard state is usually chosen as 1 atm pressure or 1 M concentration at a specified temperature, typically room temperature.
Enthalpy Change (∆H): The amount of heat absorbed or released by a reaction under constant pressure conditions.
Mole:A unit used in chemistry that represents 6.022 x 10^23 particles (atoms, molecules, ions etc.) It's like "dozen" but instead of representing 12 items, it represents an incredibly large number.