Question

A 5.00 L evacuated flask is filled with 1.86 moles NOBr. After equilibrium is established at 298 K, it is found that there are 0.082 moles of bromine gas present. Determine Kc and amp for the reaction.

Answer 1

The Kc of the given is Kc = 1.5 x 10^(-4)

Explanation:

All units should be in molarity  

Initial molarity of NOBr = moles/volume

= 1.86/5.00 = 0.372 M

2 NOBr(g) ⇔ 2 NO(g) + Br2(g)  

At equilibrium:

[Br2] = a = moles / volume = 0.082 / 5.00 = 0.0164 M

[NO2] = 2a = 0.0328 M

[NOBr] = 0.372 - 2a = 0.3392 M

Kc = [NO] ^2[Br2] / [NOBr]^2  

= 0.0328 ^2 x 0.0164 / 0.3392^2

= 1.53 x 10^(-4)

Kc = 1.5 x 10^(-4)