Chemistry Chapter 7: Thermochemistry (2 Stars) Flashcards
(39 cards)
Systems are classified based on what is or is not _______ with the surroundings.
exchanged
________ exchange neither matter nor energy with the environment.
Isolated systems
Closed systems ____ exchange energy but not matter with the environment.
can
_______ can exchange both energy and matter with the environment.
Open systems
_______ processes occur at a constant temperature.
Isothermal
________ exchange no heat with the environment.
When Q = 0, the first law simplifies to ΔU = –W
Adiabatic
_______ processes occur at a constant pressure.
Isobaric
Isovolumetric (isochoric) processes occur at a _______ volume.
constant
State functions describe the physical properties of an equilibrium state; they are pathway _______ and include pressure, density, temperature, volume, enthalpy, internal energy, Gibbs free energy, and entropy.
independent
Standard conditions are defined as ____ K, 1 atm, and 1 M concentrations.
298 K
The standard state of an element is its most prevalent form under standard conditions; standard enthalpy, standard entropy, and standard ______ are all calculated under standard conditions.
free energy
Phase changes exist at characteristic temperatures and ______.
pressures.
Fusion (melting) and freezing (crystallization or solidification) occur at the boundary between the solid and the _____ phases.
liquid
Vaporization (evaporation or boiling) and _______ occur at the boundary between the liquid and the gas phases.
condensation
Sublimation and deposition occur at the boundary between the solid and ____ phases.
gas
At temperatures above the critical point, the liquid and gas phases are ________.
indistinguishable
At the triple point, all three phases of matter exist in ________
equilibrium.
The phase diagram for a system graphs the phases and phase equilibria as a function of ______ and pressure.
temperature
Temperature and heat are/are not the same thing.
are not
Temperature is a scaled measure of the average ______ energy of a substance.
kinetic
_____ is the transfer of energy that results from differences of temperature between two substances.
Heat
The heat content of a system undergoing heating, cooling, or phase changes is the ____ of all the respective energy changes.
sum
_______ is a measure of the potential energy of a system found in intermolecular attractions and chemical bonds.
Enthalpy
Hess’s law states that the total change in potential energy of a system is equal to the changes of potential energies of the _____ steps of the process.
individual
