Chapter 12, Problem 113CP

A sample of gaseous nitrosyl bromide (NOBr) was placed in a container tiued with a frictionless, massless piston, where it decomposed at 25°C according to the following equation:

$2\text{NOBr}\left(g\right)\rightleftharpoons 2\text{NO}\left(g\right)+{\text{Br}}_2\left(g\right)$

The initial density of the system was recorded as 4.495 g/L. After equilibrium was reached, the density was noted to be 4.086 g/L.

a. Determine the value of the equilibrium constant K for the reaction.

b. If Ar(g) is added to the system at equilibrium at constant temperature, what will happen to the equilibrium position? What happens to the value of K? Explain each answer