calculate the equilibrium pressure

Question

Given that [Ni(CO)₄] = 0.200 M at equilibrium for the equation Ni(s) + 4 CO(g) ⇌ Ni(CO)₄(g) Kc = 5.00 × 10⁴ at 25.0 °C calculate the equilibrium pressure (in atm) of CO(g) at 25.0 °C.

Answer 1

Ni(s) + 4 CO(g) ⇌ Ni(CO)₄(g)

Kc = [Ni(CO)₄ ] / [CO]⁴

5.0x10⁴ = 0.2 / x⁴

x⁴ = 4.0x10^-6

x = 0.0447 M

Assume 1 liter volume, then we have 0.0447 moles of CO. Temperature is 25 + 273 = 298K. Use ideal gas law to find pressure.

PV = nRT

P = nRT/V

P = (0.0447)(0.0821)(298)/1

P = 1.09 atm