equilibria (Kp and Kc) Flashcards
what is Kc
equilibrium constant
indicates position of equilibrium for a reaction at a certain temperature
Kc =
[conc products] / [conc reactants]
(to the power of no. moles)
units of concentration
moldm-3
what is a homogenous reaction
reactants and products are in the same phase
what is a heterozygous reaction
some of the reactants and/or products are in different phases to each other
how to calculate Kc/Kp of a heterozygous reaction
any terms representing a solid are not included in the calculation
what is Kp
equilibrium constant used for gaseous equilibria
what is partial pressure
pressure of an individual substance
adds up to give total pressure
partial pressure of A =
(moles of A / total moles) x total pressure
how would ‘partial pressure of A’ be represented
PA
what are the two possible units of partial pressure
kilopascals (Kpa)
atmospheres (atm)
Kp =
product of the partial pressure of products / product of the partial pressure of reactants
(to the power of no. moles)
what factor affects equilibrium constant
temperature
what factors have no affect on equilibrium constant
concentration
pressure change
catalyst
how does temperature affect equilibrium constant
changes position of the equilibrium
if forward reaction is exothermic, equilibrium constant will decrease, because equilibrium shifts to LHS
what is Gibbs free energy (^G)
indicator of reaction feasibility
how to calculate Gibbs free energy
^G = -RT ln(K)
what ^G value shows that the reaction is feasible
^G less than or equal to zero
entropy of surroundings =
- entropy / temperature
total entropy =
R ln(K)
