equilibrium Flashcards
(23 cards)
reversible reaction
products can be turned back to reactants
dynamic equilibria
- reversible reaction
- carried out in closed system
- a state if dynamic equilibrium can be established
closed system
system where no more reactants and products are added/removed
Le Chateliers principle
factor affecting the position of equilibrium is altered
position of the equilibrium shifts to oppose the effect of the change
equilibrium disturbed by
change in conc
change in temp
change in pressure
increase in temperature
equilibrium shifts to decrease temp
shifts to ENDOTHERMIC direction
decrease in temperature
equilibrium shifts to increase temperature
equilibrium shifts in exothermic direction
enthalpy change > negative
means that forward reaction is exothermic
enthalpy change > positive
means forward reaction is endothermic
increase in concentration of substance A
equilibrium shifts to decrease amount of of substance A
decrease in concentration of substance A
equilibrium shifts to increase amount of of substance A
more H2O
equilibrium shifts to decrease amount of H2O
pressure increased
equilibrium shifts to decrease pressure
shifts to direction of fewest molecules
pressure decreased
equilibrium shifts to increase pressure
shifts to direction of most molecules
define catalysts
substance that speeds up the rate if reaction by providing an alternative reaction pathway of lower energy
what happens when a catalyst is added to reversible reaction
increase rate if of forward and backwards reaction equally
so no change to position of equilibrium
equilibrium reached faster
the Haber process formula
N2 + 3H2 ↔️ 2NH3
what is yield
amount of product made in a reaction
Haber compromise of temp
lower temp = slows rate if reaction
longer for NH3 to be produced
(higher temp = higher yield)
increase pressure = strong, expensive equipment needed
costly to produce NH3
compromise = reached to make acceptable yield in reasonable timeframe while keeping cost down
what conditions is Haber process carried out at
450°C and 200 atm (atmospheres)
whats costs involved in industrial production of ammonia
raw materials
equipment
energy
wages
catalyst used in production of ammonia
iron
Q explain in terms of equilibrium yield and cost why these conditions are used
temp
- forward reaction is endothermic
- so higher temp increases yield
- high temps are costly
pressure
- more moles of gas on RHS
- so lower pressure increases yield
- lower pressure means low cost
catalyst
- no effect on yield
- allows lower temp to be used
- lowers cost
