In: Chemistry
Given Kc = 1.5 × 1018 at 300 K for the reaction below
2 NO-----> N2 + O2
900 mg of NO were initially placed in a 1.00 L vessel and the reaction was allowed to reach equilibrium.Calculate the equilibrium concentrations of NO, N2, and O2.
Initial mass of NO = 900 mg = 0.9 g
Volume of vessel = 1.0 L
Molar mass of NO = 30.01 g/mol
Moles of NO = 0.9 / 30.01
= 0.0299 moles
Kc of reaction = 1.5 * 1018
2 NO
N2 +
O2
Initial
0.0299
0
0
Change
-
2x
+
x
+ x
Final
0.0299 -
2x
x
x
Kc = [N2][O2] / [NO]2
1.5 * 1018 = x * x / (0.0299 - 2x)2
x = 0.01495
Hence, at equilibrium:
[NO] = 0.0299 - 2*0.01495
= 0 M
[N2] = [O2] = 0.01495M