Standard enthalpy of formation (ΔHof) is heat change when 1 mol substance forms from elements. Standard states: gases at 1 atm, liquids/solids at 1 atm and 25°C, solutions at 1 M. Elements in their standard states have ΔH°f = 0
Delta symbol ∆ represents change or difference in chemistry. Delta H (enthalpy) measures total energy within a system. Delta S (entropy) quantifies degree of randomness or disorder
Thermodynamics studies energy transformations in various systems. Four laws govern energy behavior: Zeroth, First, Second, and Third. Energy exists in forms like kinetic, potential, thermal, chemical, electrical, and nuclear
Enthalpy (H) represents total heat energy in a thermodynamic system. Enthalpy equals internal energy plus pressure-volume product (H = U + PV). Enthalpy is measured in joules per mole (J/mol) or calories per mole (cal/mol)
Enthalpy is the sum of internal energy and pressure-volume product of a system. It is a state function that depends only on initial and final states. Enthalpy is measured in joules per mole (J/mol) or British Thermal Unit (BTU)
Table contains thermodynamic values for various compounds and their states. Values include enthalpy, entropy, and Gibbs Free Energy. Data organized by chemical formula and state of matter