At 525 C, K p = 0.250 for CO₂ (g) + H₂ (g) CO (g) + H₂ O (g). If enough CO₂ and H₂ is injected into a container so that CO₂ and H₂ each exert a partial pressure of 1.000 atm (P total = 2.000 atm), what is the final partial pressure of H₂ at equilibrium at 525 C?

Question

At 525 C, K p = 0.250 for CO₂ (g) + H₂ (g)  CO (g) + H₂ O (g). If enough CO₂ and H₂ is injected into a container so that CO₂ and H₂ each exert a partial pressure of 1.000 atm (P total = 2.000 atm), what is the final partial pressure of H₂ at equilibrium at 525 C?

Quizplus · Accepted Answer

The given equilibrium equation is:

CO₂ (g) + H₂ (g) <=> CO (g) + H₂ O (g)

K p = 0.250 at 525 °C

Let's assume at equilibrium "x" atm of H₂ gets consumed to produce CO and H₂O.

So, the equilibrium partial pressures will be:

P CO₂ = 1.000 atm
P H₂ = (1.000 - x) atm
P CO = x atm
P H₂O = x atm

Now, let's use the equilibrium constant expression and plug in the given values:

K p = P CO x P H₂O / P CO₂ x P H₂

0.250 = x² / (1.000 x (1.000 - x))

x = 0.667 atm

Therefore, the partial pressure of H₂ at equilibrium is 0.667 atm, which is given in choice (C).

At 525 C, K P = 0