9B.3 Flashcards
how do we maximise profits in the chemical indursty
by finding out how to convert the reactant to products as quickly and as completely possible
how is ammonia manufactured
through the direct synthesis of hydrogen and nitrogen in the harbor process
what temp and pressure is usually used in the harbor
the temperature of 450 c and pressure of 250(atm)
why is the temperature of 450 c used
the reaction between nitrogen and hydrogen is extremely slow at room temperature since the strong bond triple nitrogen bond requires high activation energy so we need a higher temperature, but even with high temperature we need a suitable catalyst to produce the yield we need, and we cant use a catalyst at lower temperature since it doesn’t work efficiently. using an extremely high temperature would increase the successful collisions but it would be economically nonfinancial since it requires a lot of money, as well as it might decrease the yield of ammonia since the backward reaction is endothermic THIS MIGHT BE DEBATABLE SINCE THE REACTION MIGHT NOT STAY A LONG TIME IN THE CHAMBER so for this reasons we a 450 c
whys is a pressure of 250 used
because a lower pressure would cause a decrease in yield and a higher pressure would require a lot of money and it might cause explosions, so a compromise of 250 atm is used
what is done with the unreacted hydrogen and nitrogen to increase efficiency
it is mixed with fresh nitrogen and hydrogen and fed back into the camber
what is the theoretical yield of ammonia in the harbor process
just over 30%
what is the actual yield of ammonia in the harbor process
15%
what are the conditions of the contact process
450 c and 2 atm
why do we use the 450 c for the contact process
using a higher temperature is better in order for the catalyst to work more efficiently even though a lower temperature would increase the rate of the forward reaction
why is 2 atm used
it is enough pressure to keep a constant flow of gas through the reaction chamber, any pressure higher than this is not necessary since the yield is already very high
what is the chemical reaction plus the enthalpy change of the contact process
H= -96 reation in page 253
what is the chemical reaction plus the enthalpy change of the harbor process
H= -92 reaction in page 252
what is the yield of the contact process
97%
what is the catalyst used in the contact process
vanadium(V) oxide
