Enthalpy of Formation (ΔHf): This term refers to the change in enthalpy when one mole of a substance is formed from its elements - it's like calculating the cost of making a homemade meal from scratch.
Enthalpy of Reaction (ΔHr): This term describes the total energy absorbed or released during a chemical reaction - similar to figuring out if you made or lost money after selling something you produced.
Spontaneous Process:A spontaneous process occurs without needing additional energy input once started, like an investment that continues to grow on its own without needing more funds.