The Haber Process
Reversible reactions may not go to completion but they can still be used efficiently in continous processes such as the HABER PROCESS. (used to manufacture ammonia)
RAW MATERIALS FOR THIS PROCESS:
hydrogen: from natural gas and steam
nitrogen: from fractional distillation of liquid air
The purified nitrogen and hydrogen are passed over an iron catalyst at a..
- high temperature (450 degrees)
- high pressure (200 atmospheres)
Some of the hydrogren and nitrogen reacts to form AMMONIA. (the ammonia produced can break down again into nitrogen and hydrogen)
The Haber Process extended
The reaction conditions (450 degrees with 200 atmospheres in pressure) are chosen to produce a reasonable yield of ammonia quickly.
(only some of the hydrogen and nitrogen react together to form ammonia)
CLOSED SYSTEMS: (no reactants are added and no products are removed)
- When a reversible reaction occurs in a closed system, an EQUILIBRIUM is achieved when reactions occur at exactly the same rate in each direction.
- The relative amounts of all reacting substances at equilibrium depend on the conditions of the reaction.
CHANGING REACTION CONDITIONS:
- gaseous reactions- an increase in pressure favours the reaction which produces the least no. of molecules.
- exothermic reaction- if temp is RAISED, yeild DECREASES. if temp is lowered, yeild INCREASES (it's the opposite for endothermic)