Equilibrium law Flashcards
(18 cards)
what factor can affect the value of k
temperature
what is the equilibrium constant
k, its the value of the concentration fraction at equilibrium, which gives an indication of the extent to which reactants are converted into products
do all products/reactants go into equilibrium expression
no, solids are ignored
equilibrium expression
K = [C]^(c)[D]^(d)/[A]^(a)[B]^(b), square brackets represnt concentration, lowercase letters represent moles, uppercase letters represent chemicals, products are the numerator, reactants are the demoninator
what are the units for k
they are not fixed and vary depending on the stoichiometry of the reaction
reaction quotient
Q, is a quantitative measure of the extent of a chemical reaction, the relative amounts of products and reactants present during a reaction at a given time
reaction quotient equation
K = [C]^(c)[D]^(d)/[A]^(a)[B]^(b), same as equilibrium constant
if Q=K what does this mean
the reaction has reached equilibrium, meaning that the forwards and backwards reaction rates are equal, concentration of reactants and products are constant
if Q>K what does this mean
the current concentration of products is higher relative to the reactants than at equilibrium, reaction must shift to right
if Q<K what does this mean
the current concentration of reactants is higher relative to the products than at equilibrium, reacrion must shift to left
equation to calculate K, if the reaction is reversed
1/K
equation to calculate K, if the coefficients are doubled
K^2
equation to calculate K, if the coeffiencts are halved
square root of K
ICE tables show what
the initial amount of reactants and products, the changes that occur as the system reaches equilibrium and the final values at equilibrium
process in using ICE tables
- Create ICE table and insert what you know eg: (I) initial amounts
- Calculate the change in mole n(known)
- Calculate changes (C) unknown using mole ratio (unknown/known) x change n(known)
- Calculate mol at eq (E) n(initial) – n(change)
- Calculate concentrations using C = n/V
if the value of K is between 10^-4 and 10^4
the extent of reaction is significant, appreciable concentrations of both reactants and products at equilibrium
if the value of K is larger than 10^4
almost complete reaction occurs, products concentrations is much higher than reactants concentrations
if the value of K is very small, less than 10^-4
negligible reaction occurs, concentration of reactants are considerly higher than products
