Chapter 7 - Thermochemistry Flashcards
(22 cards)
Isolated Systems
Exchange neither matter nor energy with the environment
Closed Systems
Can exchange energy but not matter with the environment
Open Systems
Can exchange both energy and matter with the environment
Isothermal Processes
processes that occur at constant temperature
Adiabatic processes
processes that do not exchange heat with the environment
Isobaric proccesses
processes that occur at constant pressure
Isovolumetric processes
processes that occur at constant volume
State functions
Describe the physical properties of an equilibrium state
- Pathway independent
- Include pressure, density, temperature, volume, enthalpy, internal energy, Gibbs free energy, and entropy
Standard Conditions
298 K, 1 atm, and 1 M concentrations
Fusion (melting)
Solid –> liquid
Freezing (crystallization)
Liquid –> solid
Vaporization (Evaporation or boiling)
Liquid –> Gas
Condensation
Gas –> Liquid
Sublimation
Solid –> gas
Deposition
Gas –> Solid
Triple Point
Solid, liquid, and gas phases exist in equilibrium
Temperature
Scaled measure of the average kinetic energy of a substance
Heat
Transfer of energy that results from differences of temperature between 2 substances
Enthalpy
Measure of the potential energy of a system found in intermolecular attractions and chemical bonds
Hess’s Law
states that the total change in potential energy of a system is equal to the changes of potential energies of the individual steps of the process
Entropy
Measure of the degree to which energy has been spread throughout a system or between a system and its surroundings
Gibbs Free Energy
Derived from both enthalpy and entropy values for a given system
- ΔG < 0: Reaction proceeds forward (spontaneous)
- ΔG = 0: Dynamic equilibrium
- ΔG >0: Reaction proceeds reverse (nonspontaneous)
