equilibrium concentration with gases

Moderators: Chem_Mod, Chem_Admin

Hannah_1G
Posts: 100
Joined: Wed Sep 18, 2019 12:22 am

equilibrium concentration with gases

Postby Hannah_1G » Tue Jan 14, 2020 5:42 pm

If the reaction is homogeneous with gas phase but the question is in terms of concentration and gives the moles of the reactants and products, is pressure ignored?

vpena_1I
Posts: 109
Joined: Sat Aug 24, 2019 12:15 am

Re: equilibrium concentration with gases

Postby vpena_1I » Tue Jan 14, 2020 7:38 pm

Yes, given moles of reactants and products, you will find molarity of each and use it to calculate Kc of the equation, not Kp. Only answer in Kp if the reactants and products are given in terms of bar or atm.

ELu 1J
Posts: 51
Joined: Thu Jul 25, 2019 12:16 am

Re: equilibrium concentration with gases

Postby ELu 1J » Tue Jan 14, 2020 8:26 pm

Yes, because the context of the problem is moles, that is what leads you to calculate Kc instead of Kp even though all substances are in gas phase.

Robin Cadd 1D
Posts: 113
Joined: Thu Jul 11, 2019 12:16 am

Re: equilibrium concentration with gases

Postby Robin Cadd 1D » Tue Jan 14, 2020 8:42 pm

Yes, because what you’re given corresponds to solving for Kc.

cassidysong 1K
Posts: 100
Joined: Fri Aug 30, 2019 12:15 am

Re: equilibrium concentration with gases

Postby cassidysong 1K » Tue Jan 14, 2020 9:44 pm

Yes. Pressure isn't involved in Kc

Ariel Davydov 1C
Posts: 110
Joined: Thu Jul 11, 2019 12:16 am
Been upvoted: 1 time

Re: equilibrium concentration with gases

Postby Ariel Davydov 1C » Wed Jan 15, 2020 12:00 am

Yes, but if asked to solve for partial pressures or Kp, you can use the Ideal Gas Law (PV=nRT) to solve for individual partial pressures and plug them into the Kp expression to solve for Kp.

BCaballero_4F
Posts: 94
Joined: Wed Nov 14, 2018 12:22 am

Re: equilibrium concentration with gases

Postby BCaballero_4F » Wed Jan 15, 2020 1:01 am

Yes in this case you can ignore pressure

Eunice Nguyen 4I
Posts: 100
Joined: Sat Aug 17, 2019 12:17 am

Re: equilibrium concentration with gases

Postby Eunice Nguyen 4I » Wed Jan 15, 2020 2:38 am

If moles of the reactants and products are included in the problem, then you'll just assume that pressure is ignored. You'd know partial pressure if the unit given is atm.


Return to “Equilibrium Constants & Calculating Concentrations”

Who is online

Users browsing this forum: No registered users and 2 guests