7 equilibrium Flashcards
in a dynamic equilibrium?
the rate of the forward reaction is the SAME as the rate of the backward reaction in a CLOSED system
and the conc of reactants and products is CONSTANT
graph of reaching equilibrium from reactants and from products
curved line up like an r + curved line down like an L until both cross and are constant
– reactants form products until eq
conc of reactants incr, conc of products decr
closed vs open system
closed: no reactant can escape the mixture
open: some is lost to surroundings (so the reaction is technically not reversed)
in an equilibrium expression, is reactants/prod or prod/reactants?
prod/reactants
in an equilibrium expression, the coefficient is?
added as a power of the conc
in an equilibium expression, what is not included from the chemical equation?
SOLIDS!!! NO SOLIDS
WE FUCKING HATE SOLIDS ok when you think abt it the particles cant rearrange so
what is Kc dependent on?
temperature
so at a fixed temp Kc is a constant
when Kc > 1,
equilibium shifts to the right,
more products
Kc for
N2 + 3 H2 == 2NH3
vs (doubled)
2N2 + 6H2 == 4NH3
the first Kc to the POWER of 2 is the new Kc
calculating Kc for the reverse equation? hwo does this affect the Kc
reverse Kc = 1/og Kc
what is the reaction quotient
ratio of products and reactats for a reaction that has NOT YET reached equilibrium
what does the size of the reaction quotient tell us
how far a reaction is from equilibiurm
which direction the reaction proceeds
what is the position of equilibrium
refers to the relative amts of products and reactants in an equilibrium mixture
what is Le Chatelier’s principle
says that if a CHANGE is made to a system at DYNAMIC EQUILIBRIUM,
position of equilibrium MOVES to minimise this change
(not required to quote but must APPLY)
increase in reactants conc effect on equilibrium
shifts RIGHT (= more product)
effects of increase in pressure on equilibrium
shifts in direction that produces SMALLER number of molecules of gas
effect of incr temperature on equilbirum shift
equilibrium moves in the ENDOTHERMIC direction to reverse the change
change in H = +
means forward is favoured (endo)
effect of catalyst on forward and backward reactions
incr rate EQUALLY
= reach equilibirum FASTER
is the equilibrium constant affected by changes to reactant/product concentration???
NOOOOOOO
but the opposite reaction is favoured until equilibrium is restored
does change in pressre affect Kc?????
NOOOO
its only changes the POSITION of equilibrium
do temp changes affect equilibrium constant
of COURSE they do
Kc increases with an endothermic reaction (+)
is Kc or position of equilibium affected by change in concnetration
position
chemical equaiton for the Haber Process
N2 (g) + 3H2 (g) <==> 2NH3 (g)
given the eqn for the haber process, N2 (g) + 3H2 (g) <==> 2NH3 (g)
how will increasing nitrogen amt affect:
1. position of equilibium
2. amount of ammonia
3. amount of hydrogen
4. Kc
- right
- incr
- decr
- unchanged
new equilibrium would be higher than original
what do [ ] mean in Kc calculations
the conc of the chemical in mol/dm3
what is the chemical formula of ethanoic acid
CH3COOH
how to deduce units for Kc
subsitute the units for the concs into the equation and cancel out
if its like mol/dm3 divided by mol/dm3 then yeah no units
equation for Gibbs free energy change? (section 1 data booklet)
gibbs free energy change = -(gas constant)(temp in K) ln(equilibium constant)
what are the units for Gibbs free energy change and R (gas constant)?
G –> kJ / mol
R –> J /K/mol
= one value needs to be adjusted by 1000
when equilibrium constant > 1, gibbs free energy change?
ΔG < 0
when Kc = 0, gibbs free energy change?
ΔG = 0
a negative ΔG value means the reaction is (spontaneous/non-spontaneous)
spontaneous!
as ΔG becomes more negative
the forward reaction is?
the value of the equilibium constant?
forward favoured
Kc increases
to find Kc from lnKc = 1.77?
lnKc = 1.77
Kc = e ^ 1.77
