Untitled - Kelly Walsh High School

210 CHEMISTRY FOR THE UTTERLY CONFUSED
Careful!
Quick Tip
A container has the following equilibrium established at 700°C:
N 2(g) 3 H 2(g) K 2 NH 3(g)
The equilibrium mixture had an ammonia concentration of 0.120 M, a nitrogen
concentration of 1.03 M, and a hydrogen concentration of 1.62 M. Determine the
value of the equilibrium constant, K c.
Temperatures often appear in equilibria problems, but most problems will not
require you to use the temperature.
The first step in this, and most equilibria problems, should begin by writing the
equilibrium constant expression. In this case, the expression is:
K c [NH 3 ]2
[N 2 ][H 2 ] 3
This step will, in most cases, get you some partial credit.
The problem gives us: [NH 3] 0.120 M, [N 2] 1.03 M, and [H 2] 1.62 M. The
next step is to enter the given values into the equilibrium constant expression
and enter the values into your calculator.
Kc 3.288367 103 3.29 103 [0.120] 2
[1.03] [1.62] 3
[NH3 ] 2
[N2 ][H2 ] 3
The equilibrium value for the following equilibrium is 2.42 10 3 at a certain
temperature. N 2(g) 3 H 2(g) K 2 NH 3(g) Determine the ammonia concentration
at equilibrium with 2.00 M nitrogen and 3.00 M hydrogen.