Chemical Thermodynamics

Discover the core concepts of chemical thermodynamics, including temperature-driven changes, system states, internal energy, first law and heat, then explore entropy, free energy, and Gibbs free energy as state functions.

Learn the three system types in chemical thermodynamics—open, closed, and isolated—and how boundaries govern matter and energy exchange, with a look at extensive and intensive properties.

Define the state of a system by fixed macroscopic properties and state variables, and identify state functions like internal energy and free energy under isothermal, isobaric, and isochoric conditions.

Explore internal energy as a state function and apply the first law of thermodynamics to quantify the change in a system during heat transfer and work, including ideal gas expansion.

Explain the limitations of the first law of thermodynamics and introduce the second law, clarifying spontaneity, energy transformations, entropy, and the role of state functions in chemical thermodynamics.

Examine state functions beyond internal energy, including entropy and pressure-volume work, and relate spontaneity and equilibrium to Gibbs free energy and maximum work at constant temperature and pressure.

Define Gibbs free energy g = h − ts and show its decrease equals the maximum useful work; relate ΔG° to K and ΔG = −nFE for galvanic cells.

Explain how exothermic and endothermic reactions occur through heat transfer, under standard state at 298 K, and illustrate enthalpies of formation, combustion, neutralization, hydration, and ionization as energy changes.

Apply Hess’s law to equate heat changes in one-step or multi-step reactions. Examine standard formation enthalpies and how their sums yield the reaction’s enthalpy.

Explore bond energy as the strength of covalent or ionic bonds, defined by dissociation energy, and learn to calculate it from a five-step solid-to-gas cycle.

Learn how a bomb calorimeter measures the heat of combustion at constant volume, linking internal energy change to calorimeter heat capacity and recorded temperature rise.

Define heat capacity and specific heat capacity, and show how heat raises temperature. Examine Cp and Cv and their use at constant pressure and constant volume.