Equilibrium -physical Flashcards
Equilibrium definition
A chemical reaction where reactant and products concentrations remain constant
Rate equation for equilibrium
K= [C]^c [D]d/[A]a [B]b
Where a,b,c,d
If the equilibrium position lies to the left
Products < reactants
K<1
More reactants than products
If the equilibrium position lies to the right
Products >reactants
K>1
Equilibrium constant rules
Not affected by concentration and pressure
When temperature increases the value of K increases for the endothermic reaction
When temperature decreases the value for K increases for the exothermic reaction
Endothermic enthalpy change
Positive
Exothermic enthalpy change
Negative
Water equilibrium
H2O +H2O —> H3O+ +OH-
Kw formula
Kw = [H3O+] [OH-]
=1.01x10^-14
Kw rules
Affected by temperature
pH formula
pH = -log[H+]
H+ concentration formula
10^-pH
Concentration calculation and pH calculation tips
Always write out the dissociation equation
Strong acids
Acids that completely dissociate into ions in aqueous solution
Strong bases
Bases that completely dissociate into ions
Weak acids
Acids which partially dissociate into ions in aqueous solution
Weak bases
Bases which partially dissociate into ions in aqueous solution
Strong acids examples
Hydrochloric, nitric and sulphuric.
Weak acids examples
Ethanoic, sulphurous and carbonic
Strong bases examples
Metal hydroxides and oxides
Weak bases examples
Ammonia and amines