Equilibrium Constant of A(g) 2B(g)+C(g) at Temperature t

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Discussion Overview

The discussion revolves around calculating the equilibrium constant (Kc) for the reaction A(g) <--- 2B(g) + C(g) at a specified temperature t, given initial conditions and equilibrium concentrations. The scope includes mathematical reasoning and conceptual clarification regarding equilibrium expressions.

Discussion Character

  • Mathematical reasoning
  • Technical explanation
  • Homework-related

Main Points Raised

  • One participant presents the initial setup of the reaction and provides the equilibrium concentration of C as 0.050 mol/L, seeking to find Kc.
  • Another participant proposes a method for calculating Kc using the equilibrium concentrations, but their calculation appears unclear and may contain errors.
  • A third participant emphasizes the importance of determining the initial concentration of A and the stoichiometry of the reaction to find the equilibrium concentrations of A and B.
  • Some participants discuss the form of the equilibrium constant expression, with one suggesting it should be Kc and another providing a general formula for Kc based on the concentrations of the reactants and products.
  • There is a mention of the relationship between the moles of B and C at equilibrium, with a participant noting that the concentration of B should account for its stoichiometric coefficient.
  • One participant questions the setup of the equilibrium expression and requests clarification on the calculations involved.

Areas of Agreement / Disagreement

Participants express various methods for calculating Kc and discuss the setup of the equilibrium expression, but there is no consensus on the correct approach or final value of Kc. Disagreements exist regarding the interpretation of the equilibrium concentrations and the proper formulation of the equilibrium constant.

Contextual Notes

Some participants' calculations and assumptions may depend on the interpretation of the initial conditions and the stoichiometry of the reaction, which remain unresolved. The discussion does not clarify the exact values or methods to be used for the calculations.

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A(g) <---
<--- 2B(g) + C(g)

When 1.00mol of A is placed in a 4.00L container at temperature t, the concentration of C at equilibrium is 0.050mol/L. What is the equilibrium constant for the reaction at temperature t?

Thanks for the help.
 
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A(g)-> 2B(g)+ C(g)
1mol
(1-x)/4 2x/4 x/4
they have given that x=0.05mol/L
kc= (0.05/4*0.01/16)/0.95/4
=1/19*100mol/L
 
ChemRookie said:
A(g) <---
<--- 2B(g) + C(g)

When 1.00mol of A is placed in a 4.00L container at temperature t, the concentration of C at equilibrium is 0.050mol/L. What is the equilibrium constant for the reaction at temperature t?

Thanks for the help.

OK let's look at the problem. First what is the initial concentration of A. Second given the stoichiometry of the problem and the value of C at equilibrium what are the concentrations of A and B ? Finally how due you write the equilibrium constant (and don't forget powers). Due the math ;)
 
campa said:
A(g)-> 2B(g)+ C(g)
1mol
(1-x)/4 2x/4 x/4
they have given that x=0.05mol/L
kc= (0.05/4*0.01/16)/0.95/4 =1/19*100mol/L

can u explain to me how u set that up? and how do you solve it? (do the calculations)
 
Ka= [2x]^{2}[x]/[initial conc.-x]

Can you explain to us why it'll be in such a form?
 
the equilibrium constant for the reaction at temperature t should be Kc so considering
the moles used to start this reaction which is 1mol of A(g) you can determine the moles used to get the right side of the equation at equilibrium. So the moles used from A(g) should be (1-x)moles and they have given that at equilibrium the concentration of C is 0.05mol(x=0.05) and it equals to the concentration of B(g) but there are two moles of B so it should be 2*0.05
and by deviding these moles by the volume of the container you get mol/L of each gas
kc= [C(g)] *[B(g)]*[B(g)]/[A(g)]

I hope this helps and my guess is that it should be 0.05mol and not 0.05mol/L
 
Last edited:

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