Problem 5G-9

[Lilly Catarozoli 1B]

In this textbook problem, it says although (PO2)3/(PO3)2 is the same, (PO2)/(PO3) will be different. Why is this the case? I thought that they would both be the same. Thanks!

[Andre Fabian 1F]

In this textbook problem, it says although (PO2)3/(PO3)2 is the same, (PO2)/(PO3) will be different. Why is this the case? I thought that they would both be the same. Thanks!

Mathematically, they are different because one has the partial pressures raised to different exponents, while the other does not. Conceptually, the former is correct in calculating Kp, because you need to factor in the species coefficients to solve for the partial pressure equilibrium.


Hope this helps!

[Natalie Do 3F]

The exponents make a huge difference like Andre said. If you replaced the concentrations with arbitrary numbers, you could see mathematically this is true. PO2 in the original is an entire factor higher than PO3 and the different exponents significantly impact the total concentration which is why it is important to balance equations.

[Hasmik Dis 2F]

The exponents mathematically change the answer completely. Also, it is important to realize that those exponents also represent the ratios of which each substance exists in the reaction. Account for the different ratios will also change your answer than merely dividing out the substances.