Equilibrium Flashcards
Reversible reaction
One that goes in both directions at the same temperature
How do you know when a system has reached equilibrium?
When there is no further change in the concentrations of the reactants and products
Dynamic equilibrium
The rates of forward and reverse reaction are equal, so there is no further change in the concentrations of reactants and products
Le Chatelier’s principle
When the conditions of a system in equilibrium are altered, the position of equilibrium alters in such a way as to try to restore the original conditions
Dynamic
The forward and reverse reactions are both taking place
Equilibrium
Reactions take place at same speed, all reactants and products are present, and the concentration of all reactants and products remain constant
4 factors affecting the position/rate of equilibrium
Concentration, pressure, temperature and catalysts
What do the Haber process and the Contact process produce?
Ammonia (NH3) and sulphuric acid (H2SO4)
Haber process equation
N2(g) + 3H2(g) 2NH3(g)
Conditions for Haber process
200 atm pressure, 380-450oC temperature, iron catalyst
3 steps in the Contact process
1) Make sulphur dioxide
2) Convert sulphur dioxide into sulphur trioxide
3) Convert sulphur trioxide into concentrated sulphuric acid
2 ways to make sulphur dioxide (+ equations)
1) Burn sulphur in excess air: S(s) + O2(g) -> SO2(g)
2) Heat sulphide ores (e.g. pyrite) in excess air: 4FeS2(s) + 11O2(g) -> 2Fe2O3(s) + 8SO2(g)
Formula for the conversion of sulphur dioxide to sulphur trioxide, endo or exo?
2SO2(g) + O2(g) 2SO3
Exothermic
Conditions for conversion to sulphur trioxide in Contact process
1) 1:1 ratio of sulphur dioxide to oxygen
2) 400-450oC temperature
3) 1-2 atm pressure
4) V2O5 catalyst
Equations to convert sulphur trioxide to sulphuric acid
H2SO4(l) + SO3(g) -> H2S2O7(l) - called fuming sulphuric acid
H2S2O7(l) + H2O(l) -> 2H2SO4(l)
