## 5G.9

Gabriella Bates 2L
Posts: 113
Joined: Thu Jul 11, 2019 12:15 am

### 5G.9

In the solutions for 5G.9, the book writes the equilibrium constants using the concentrations opposed to the partial pressures. However, since the products and reactants are gasses, wouldn't it be more correct to use the partial pressure? Thanks in advance

Asha Agarwal 1E
Posts: 51
Joined: Fri Aug 30, 2019 12:16 am

### Re: 5G.9

When calculating the equilibrium constant and reaction quotients, they can be calculated in terms of concentrations or partial pressures regardless of reactant and product phases. Calculating the ratios uses only gases and aqueous species, so it makes sense that when calculating the equilibrium constant in terms of molar concentration, you would be using the concentrations of the gases in the reaction.

Hiba Alnajjar_2C
Posts: 108
Joined: Fri Aug 09, 2019 12:17 am

### Re: 5G.9

I believe that the answer to this question can either be in terms of partial pressures or concentrations since it doesn't specify whether it wants Kc or Kp. I believe that partial pressures are more commonly used for gases as opposed to concentrations, but both options are correct.

Hannah Lee 2F
Posts: 117
Joined: Thu Jul 11, 2019 12:15 am

### Re: 5G.9

I agree! The equilibrium constant can be defined in terms of either Kp or Kc. You look at the values given to you to determine whether you will be calculating Kp or Kc - for instance, if the problem gives you moles and volumes, you will probably be using Kc, but if the problem gave you partial pressures in terms of atm, you would probably be using Kp. You can also convert between Kp and Kc using an equation, although I'm not sure if that's listed in the outline.