Haber Process Flashcards
What is the ideal temperature for the RATE of production of ammonia in the Haber process
Ideal is a high temperature because it increases the average kinetic energy of particles. This increases the frequency of collisions. And the proportion of particles that can overcome activation energy barrier. This increases the frequency of successful collision, which increases the rate of reaction
What is the ideal temperature for the YIELD of ammonia in the Haber process
Ideal is low temperature because a low temperature deceases both rates as average kinetic energy is lowered (just say as discussed above). The endothermic rate is lowered more than the endothermic rate as it has a higher activation energy, so is proportionally lowered more. The reverse rate is endothermic, hence the forwards rate overtakes the reverse shifts equilibrium right, and increasing yield.
What is the ideal pressure for the RATE of ammonia in Haber
Ideally a high pressure. There are more particles per volume which increases collision frequency. This increases both forwards and reverse rate of reaction immediately.
What is the ideal pressure for the YIELD of ammonia in Haber
Ideally a high pressure. Both the forwards and rev rates are increased immediately discussed above. However the forwards rate increases more because there are more molecules colliding on the reactant side. This is seen by the greater sum of molar coefficients on this side. Forwards rate overtakes the reverse rate shifting equilibrium right and increasing yield.
What is the effect of a catalyst on the RATE of ammonia production in Haber
Ideally a catalyst is used. It provides an alternate reaction pathway with lower activation energy increasing the proportion of particles that overcome it. This increases the frequency of successful collisions and hence increases both the forwards and reverse reaction rate.
What is the effect of a catalyst on the YIELD of ammonia in Haber
A catalyst would have no effect on yield. Both rates are equally increased as discussed above so no rate overtakes the other, and there is no net effect on the position of equilibrium
What is an important consideration for the molar ratios of reactants in Haber
A molar ratio of 1:3 would ideally be used. This ensures that none of the reactants is limiting (although if one was, it would preferrably be H2 so slightly more N2)
Why would you remove ammonia from the system after in has been produced via fractional distillation
The removal of NH3 decreases the concentration of this particle and therefore the frequency of collisions. The reverse rate is decreased, while there is no initial change in forwards rate. This results in the forwards rate overtaking the reverse, shifting equilibrium right. This gives a higher yield of ammonia.
