Hi this question is on my study guide and I want to make sure I get to the right answer and know why.

Question

Calculate K for the synthesis of ammonia at 400°C
N2(g) + 3 H2(g) —> 2 NH3(g)
<—
, if the following concentrations are present at equilibrium: N2(g)= 1.2 mol/L, H2(g) = 0.80 mol/L, and NH3(g) = 0.28 mol/L.
(Subscript 2 in N2, 3 H2, and subscript 3 in 2 NH3, double arrows in reaction)

Answer 1

Write the equilibrium K expression.
Substitute the numbers for the concentrations shown at equilibrium.
Calculate K.
I'll be glad to check your work if you post it.

Answer 2

K = (0.28)^2 / 1.2 ( 0.80)^3 =1.28 x 10^-1 ?

Answer 3

I agree. Good work. If your prof is picky about significant figures, s/he will object to using 3 s.f. in the answer when you have only 2 in the numbers; therefore, you may want to round that final answer to 0.13

Answer 4

Thanks