Consider the equilibrium: 2N2O (g) + O2 (g) = 4NO (g)
3.00 moles of NO (g) are introduced into a 1.00 liter evacuated flask. When the system comes to equilibrium, 1.00 moles of N2O (g) has formed. What are the equilibrium concentrations of each substance? What is Kc for the reaction?

Question

Consider the equilibrium: 2N2O (g) + O2 (g) = 4NO (g) 
3.00 moles of NO (g) are introduced into a 1.00 liter evacuated flask. When the system comes to equilibrium, 1.00 moles of N2O (g) has formed. What are the equilibrium concentrations of each substance? What is Kc for the reaction?

Owen Ambrose · Accepted Answer

The equilibrium concentrations are [N₂O] = 1.00 mol/L; [O₂] = 0.50 mol/L; [NO] = 1.00 mol/L. #K_"c"# = 2.0.

First, write the balanced chemical equation with an ICE table.

2N₂O + O₂ ⇌ 4NO

I/mol·L⁻¹: 0; 0; 3.00
C/mol·L⁻¹: +2#x#; +#x#; -4#x#
E/mol·L⁻¹: 2#x#; #x#; 3.00 - 4#x#

At equilibrium, [N₂O] = 2#x# mol/L= 1.00 mol/L.

So #x# = 0.50

Then [O₂] = #x# mol/L = 0.50 mol/L

and [NO] = (3.00 - 4#x#) mol/L = (3.00 – 4×0.50) mol/L = 1.00 mol/L

#K_"c" = (["NO"]^4)/(["N"_2"O"]^2 ["O"₂]) = 1.00^4/(1.00^2 × 0.50)# = 2.0

Cooper Adams · Answer

undefined The equilibrium concentrations are: [N2O] = 1.00 M, [O2] = 1.00 M, [NO] = 2.00 M. The equilibrium constant, Kc, for the reaction is 4.

Consider the equilibrium: 2N2O (g) + O2 (g) = 4NO (g) 3.00 moles of NO (g) are introduced into a 1.00 liter evacuated flask. When the system comes to equilibrium, 1.00 moles of N2O (g) has formed. What are the equilibrium concentrations of each substance? What is Kc for the reaction?