1.7 equilibrium and acid based reactions Flashcards
what is meant by dynamic equilibrium?
the rate of the forward and backward reaction is the same; there is no further change in the concentrations of reactants and products. can only occur in closed system
state Le Chatelier’s Principle:
if a change is made to the conditions of a reversible reaction, the position of equilibrium will move to counteract the change
exothermic reaction
- forward reaction releases heat
- negative delta H
endothermic reaction
- backwards reaction absorbs heat
- positive delta H
what is meant by reversible equilibrium?
chemical reaction in which the reactants react to form the products and simultaneously the products again form the reactants made to go in either direction depending on condition
what is the position of equilibrium influenced by?
temperature, pressure and concentration
effect of increased temperature
favours the endothermic reaction:
- system will decrease therefore favouring the backwards reaction moving to the LHS
- higher temp = faster rate of reaction
effect of decreased temperature:
favours the exothermic reaction:
-system will increase there equilibrium position will move towards RHS, favouring forward position
effect from catalyst:
increases rate of both the forward and backwards reaction so no observational change/affect
effect of increased pressure:
Increasing the pressure moves the position of equilibrium to whichever side of the equation has fewer gas molecules.
effect of decreased pressure:
decreasing the pressure moves the position of equilibrium to whichever side of the equation has more gas molecules.
effect of increase concentration of reactants:
favours the forward reaction
effect of increase concentration of product:
favours the backwards reaction
what is equilibrium constant? (Kc)
Kc is the equilibrium constant in terms of concentration.
In general for an equilibrium: aA + bB ⇌ cC + dD
The value of Kc is not affected by pressure or concentration.
It is only affected by temperature.
what is meant by homogeneous equilibrium?
has everything present in the same phase
what is meant by heterogeneous equilibrium?
has things present in more than one phase
how do you know something is an acid?
contains H+ ions proton donor
how do you know something is a base?
contains H+ proton acceptor
strong acids
strong acids are acids that dissociate completely when dissolved in water
weak acids
partially dissociated when dissolved in water e.g ethanoic acid
