Flashcards in General Chemistry Chapter 7: Thermochemistry Deck (24)
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1
Isolated systems
exchange neither matter nor energy with the environment
2
Closed systems
exchange energy, but not matter with the environment
3
Open systems
exchange both energy and matter with the environment
4
Isothermal processes
Occur at a constant temperature
5
Adiabatic processes
exchange no heat with the environment
6
Isobaric processes
occur at a constant pressure
7
Isovolumetric (isochoric)
occur at a constant volume
8
State functions
describe the physical properties of an equilibrium state; they are pathway independent and include pressure, density, temperature, volume, enthalpy, internal energy, Gibbs free energy and entropy
9
Standard conditions
defined as 298 K, 1 atm and 1 M concentrations
10
Standard state
It's most prevalent from under standard conditions; standard enthalpy, standard entropy and standard free energy are all calculated under standard conditions.
11
At temperatures about the critical point:
liquid and gas phases are indistinguishable.
12
Triple point
All three phases of matter exist in equilibrium
13
Phase diagram
graphs the phases and phase equilibria as a function of temperature and pressure
14
Temperature
a scaled measure of the average kinetic energy of a substance
15
Heat
The transfer of energy that results from differences of temperature between two substances.
16
Enthalpy
The measure of the potential energy of a system found in intermolecular attractions and chemical bonds
17
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
18
Entropy
While often though of as disorder, it is a measure of the degree to which energy has been spread throughout a system or between a system and its surroundings
19
What is the units for Entropy?
heat transferred per mole per unit K
20
When in entropy maximized?
at equilibrium
21
G
reaction proceeds forward (spontaneous)
22
G = 0
reaction is in dynamic equilibrium
23
G > 0
reaction proceeds in reverse direction (nonspontaneous)
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