Thermodynamics Flashcards
temp conversions
F = (9/5)C + 32
K = C + 273
thermal expansion
ΔL = αLΔT
volumetric thermal expansion
ΔV = βVΔT
β = 3α
isolated systems
- not capable of exchanging energy or matter with their surroundings
- total change in internal energy must be zero
- bomb calorimeter
closed systems
- capable of exchanging energy but not matter w the surroundings
- like gases in vessels
open systems
- can exchange both matter and energy
state functions
pressure, density, temp, volume, enthalpy, internal energy, gibbs free energy, entropy
process functions
describe the path taken to get from one state to another
heat, work
change in internal energy
ΔU = Q - W
+W
work is done by system (expansion)
-W
work is done on the system (compression)
heat unit conversions
1 Cal = 10^3 cal = 4184 J = 3.97 BTU
conduction
the direct transfer of energy from molecule to molecule through molecular collisions
convection
the transfer of heat by the physical motion of a fluid over a material
radiation
energy transfer by EM waves
specific heat
energy (cal or J) per g•K it takes to raise one gram of a substance by one degree
heat gained or lost by system NOT phase change
q = mcΔT
heat gained or lost by system DURING phase change
q = mL
L = latent heat
isothermal rxn
ΔU = 0
Q = W
P-V graph: negative exponential
adiabatic
Q = 0
ΔU = -W
P-V graph: negative exponential
isobaric
constant pressure
P-V graph: horizontal line
isovolumetric (isochoric)
W = 0
ΔU = Q
P-V graph: vertical line
change in entropy
ΔS = Qrev/T
- T is in kelvin
- Qrev is the heat gained or lost in a reversible rxn
- entropy is in J/(mol•K)
ΔS universe
ΔSuni = ΔSsys + ΔSsurr > 0
