Haber Process Flashcards
what is the haber process
a reversible reaction between nitrogen and hydrogen to form ammonia
what are the are materials used in the haber process
air, natural gas and water
how is nitrogen and hydrogen obtained
by the fractional distillation of liquid air - nitrogen
by reacting natural gas with steam - hydrogen
why is ammonia removed from the system as its formed
when ammonia is removed, the position of equilibrium moves to the right increasing the yield. Ammonia is removed to prevent the reverse reaction from taking place
why is the unreacted nitrogen and hydrogen recycled
to make the process economical and because hydrogen is explosive and highly flammable so must not be released into the atmosphere
why is iron used in the manufacture of ammonia
as a catalyst to speed up the rate of reaction
why is the catalyst used often in the form of fine pellets
fine pellets have a large surface area so the rate of reaction is faster
what is the chemical equation for the haber process
N2 + 3H2 ———–> 2NH3
<———–
is the reaction between nitrogen and hydrogen endothermic or exothermic
exothermic
what are the conditions of the haber process
temperature of 450 degrees celsius, pressure of 200 atm and an iron catalyst
why is a temperature of 450 degrees celsius used
as the forward reaction is exothermic, a low temperature increases the yield of ammonia. However, a low temperature is not used because the rate of reaction is too slow at low temperatures. A high temperature is not used because it moves the position of equilibrium to the left and decreases the yield. So 450 is used as a compromise
why is a pressure of 200 atm used in the haber process
a high pressure would shift the position of equilibrium to the right and increase the yield and the pressure but would be too expensive so 200 atm is used as a compromise
why is it expensive to use a high pressure in the haber process
high cost of energy needed to generate the pressure
high cost for making pipes and reactors thicker to withstand the pressure
high cost for maintaining the equipment
what are the uses of ammonia
make fertilisers such as ammonium nitrate
manufacture nitric acid
what elements are found in fertilisers
nitrogen, phosphorous and potassium compounds
