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Hi guys,
Don't usually post here but this question is driving me crazy.
TBR Gen Chem I, Chp. III, passage XIV, q#95.
Consider the following endothermic equation:
1 N2O4(g) <--> 2NO2(g)
As the handle of a piston container filled with an equilibrium mixture of NO2 and N2O4 is lifted, what occurs?
I.The PNO2/PN2O4 ratio increases.
II. The piston cools down
III. The mole percent of N2O4 increases.
Answer is I+II. II is obviously true (endothermic), but here's what I don't get. The Kp (Keq) of a reaction is fixed; the ratio of products to reactants will not change except due to temperature. While it is true that there is dynamic equilibrium, and the denominator can rise if the numerator rises proportionally, the ratio cannot change.
In our piston example, as the piston handle is lifted, we now have more volume that we need to fill and maintain pressure. The equation will shift to the right.
Why does the ratio of PNO2/PN2O4 increase however if it has to obey the Keq constant?
Don't usually post here but this question is driving me crazy.
TBR Gen Chem I, Chp. III, passage XIV, q#95.
Consider the following endothermic equation:
1 N2O4(g) <--> 2NO2(g)
As the handle of a piston container filled with an equilibrium mixture of NO2 and N2O4 is lifted, what occurs?
I.The PNO2/PN2O4 ratio increases.
II. The piston cools down
III. The mole percent of N2O4 increases.
Answer is I+II. II is obviously true (endothermic), but here's what I don't get. The Kp (Keq) of a reaction is fixed; the ratio of products to reactants will not change except due to temperature. While it is true that there is dynamic equilibrium, and the denominator can rise if the numerator rises proportionally, the ratio cannot change.
In our piston example, as the piston handle is lifted, we now have more volume that we need to fill and maintain pressure. The equation will shift to the right.
Why does the ratio of PNO2/PN2O4 increase however if it has to obey the Keq constant?