reversible rxns Flashcards
How do you know mixture is at equilibrium for reversible rxns
Conc of reactants and products are constant
rate of forward reactions is equal to the rate of backward reaction
Why wld rate of forward reaction fall as time goes onq
As A and B reacts, their concentrations falls and frequency of collision of their particles falls, so rate of reaction falls
Why rate of reverse reaction increase with time
concentrations of the products in mixture increase and freqeuncy of collision between particles increase. Thus, with time, the rate of reaction between C and D increases
Le Chatelier’s Principle
If a system at dynamic equilibrium is subjected to a small change, the equilibrium’s response is to counteract the change so as to minimise the effect of the change
Template: When does the reaction reach equilibrium (use N2 + 3H2 2NH3 [exothermic] )
speed in which nitrogen and hydrogen react to give ammonia and heat is the same as the speed in which ammonia breaks up by absorbing heat to give nitrogen and hydrogen
if forward rxn is exothermic and temp increase, wot happen
both rates of forward and backwards reactions increase. however, rate of forwards reaction increases less than rate of backward reaction, thus position of equilibrium shifts left.
If forward rxn is exothermic and temp decrease, what happen
Both rates of forward and backward reaction decrease. However, rate of fwd reaction decreases less than backward rxn thus position of equilibrium shifts right
if forward rxn is endothermic and temp increase, wot happen
rate of forward rxn increases mor than rate of backward reaction, thus position of equilibrium shift right
if forward rxn is endothermic and temp decrease, wot happen
rate of forward rxn decreases more than rate of backward reaction, thus position of equilibrium shifts left
Answer technique for le chaletiers principle (pressure decrease)
According to Le Chateliers Principle, as pressure decrease, system counteract this decrease in pressure, by increasing pressure, favouring the ________ rxn, by increasing total no of gas molecules, shifting equilibrium position to __________, and thus product/reactant yield______
Answer technique for le chatleier principle (forward reaction is endothermic and tempo increase)
if temp is increased, according to let Chat principle, system counteracts this increased temp by removing heat, thus favouring forward endothermic rxn so position of equilibria shifs right and yield of product increase
