Calculating Equilibrium Concentrations Practice Test

At 427°C, $$K_c = 55.3$$ for $$\text{H}_2(g) + \text{Br}_2(g) \rightleftharpoons 2\text{HBr}(g)$$. If the initial concentrations are $$\text{H}_2 = 0.200 \text{ M}$$, $$\text{Br}_2 = 0.100 \text{ M}$$, and $$\text{HBr} = 0.300 \text{ M}$$, what is the equilibrium concentration of $$\text{Br}_2$$?

The synthesis of hydrogen chloride is represented by $$H_2(g) + Cl_2(g) \rightleftharpoons 2HCl(g)$$, which has a large equilibrium constant, $$K_p = 2.5 \times 10^{4}$$, at a certain temperature. If 1.0 atm of $$H_2$$ and 1.0 atm of $$Cl_2$$ are mixed in a container, what will be the approximate partial pressure of $$H_2$$ at equilibrium?