Calculating K for gases
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Calculating K for gases
I was wondering how we know if the answer is looking for Kc or Kp when looking at a reaction of gases. Sometimes, we're given the concentration of the gases but also the temperature the reaction is occurring at, so I get confused if we're supposed to convert concentration into pressure and then find Kp, or just find Kc and the temperature is just extra information that was given. Sorry if this is confusing in any way!
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Re: Calculating K for gases
I think if they wanted Kp, they would specifically ask for the pressures or say Kp. When the concentrations are given in gas with the temperature listed, it is still Kc. I am not too sure when you would consider it being Kp(maybe when the temperature were to change in the middle??)
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Re: Calculating K for gases
Can you give any specific example where the questions are inconsistent with concentration and pressure?
(Like gives Kc but the partial pressure of gas molecules?)
Usually, it only gives one of these two.
If the question is tricky on that, you will need to convert Kc and Kp using Kp=Kc(RT)Δn, and c(RT)=P. Rare but not difficult to do.
Hope this helps.
(Like gives Kc but the partial pressure of gas molecules?)
Usually, it only gives one of these two.
If the question is tricky on that, you will need to convert Kc and Kp using Kp=Kc(RT)Δn, and c(RT)=P. Rare but not difficult to do.
Hope this helps.
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Re: Calculating K for gases
In the examples that I've seen in this class, the temperature is usually given either as extra information for context or for you to use to eventually calculate Q instead of Kc or Kp if they tell you that the temperature is not the same at equilibrium or something like that. I'd say that if the question gives you concentrations to begin with, then it's safe to continue using those concentrations to find Kc. If it's impossible or difficult to do so, you can try converting to pressure.
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