© www.chemsheets.co.uk GCSE 112 18-Jul-13

NH3

PRODUCTION OF AMMONIA

NH3

Millions of tonnes per year

cleaning fluid

fertiliser

MAKING AMMONIA

MAKING AMMONIA

RAW MATERIALS

N2(g) + 3 H2(g) 2 NH3(g)

airmethan

e + steam

ammonianitrogen hydrogen

© www.chemsheets.co.uk GCSE 112 18-Jul-13

MAKING AMMONIA

N2(g) + 3 H2(g) 2 NH3(g)

exothermic

endothermic

4 molecules 2 moleculesmore pressure less pressure © www.chemsheets.co.uk GCSE 112 18-Jul-13

MAKING AMMONIA

MAKING AMMONIA

N2(g) + 3 H2(g) 2 NH3(g)

Temperature450ºC

• Lower temperature → more NH3

• Reaction exothermic• Higher temperature → faster• Compromise between yield &

ratePressure 200 atm

• Higher pressure → more NH3

• 4 molecules → 2 molecules• Higher pressure → very

expensive• Compromise between yield &

costCatalyst iron • Speeds up reaction

• No effect on yield of NH3

© www.chemsheets.co.uk GCSE 112 18-Jul-13

MAKING AMMONIA

N2(g) + 3 H2(g) 2 NH3(g)

• NH3 is removed by cooling (forms a liquid).

• Less than 30% yield, so the unreacted H2 and N2 are recycled.

© www.chemsheets.co.uk GCSE 112 18-Jul-13