Thermodynamics Flashcards
differentiate system and surroundings
system = reaction surroundings = everything else
differentiate between types of systems
isolated: heat, matter, work can’t enter/leave system
adiabatic: heat, matter can’t enter/leave
closed: matter can’t enter/leave
open: -
describe state functions
have unique values once state of system is defined. therefore depend on only initial and final states of ysstem
what are state functinos
4 functions
temp volume pressure
describe path functions
depend on the way that cthe change in the initial and final states of the system occur - heat and work
define: internal energy
a system’s total energy - nuclear, electronic, interaction, vibrational, rotational and translational
delta U of an isolated system
because no energy or matter can enter/leave a system, delta U = 0
Describe enthalpy
heat transfer from system to surroundings
describe exothermic and endothermic
o ΔH<0: exothermic; heat transferred from system to surroundings
o ΔH>0: endothermic; heat transferred from surroundings to system
enthalpy equation?
ΔH = ΔU + pΔV
J) (J) (Pa)(m3
what is standard enthalpy?
enthalpy under pressure of 100kPa (1M conc) and usually 25*c
describe standard enthalpy of formation
enthalpy change accompanying creation of one mole of a substance in standard state from constituaent elements in standard states
describe standard enthalpy of reaction
Sum of the enthalpy of formation of the products – sum of enthalpy of formation of reactants.
describe first law of thermodynamics
energy is conserved
heat and work have equivalent effects
the only way energy can be transferred is through heat and work
ΔUuniverse = ΔUsystem + ΔUsurroundings = 0
ΔUsystem = q + w
since work = -PΔV, ΔUsystem = q – PΔV
conditions of constant volume?
ΔUsystem = q
