Question #1eb65

1 Answer
Nov 10, 2015

Here's what I got.

Explanation:

I'm not sure I followed what you did there, so I'll just solve it completely here.

So, you know that you're dealing with an equilibrium reaction between nitrogen gas, "N"_2N2, oxygen gas, "O"_2O2, and nitric oxide, "NO"NO.

Notice that the equilibrium constant ** for this reaction, K_cKc, is smaller than 11, which means that the equilibrium will lie to the left**, i.e. it will favor the reactants more than the product.

Now, your reaction starts with only product, which means that you can expect the reverse reaction, i.e. the one that leads to the consumption of "NO"NO and the formation of "N"_2N2 and "O"_2O2, to be favored.

The magnitude of the equilibrium constant tells you that most of the nitric oxide will be converted to nitrogen and oxygen, which implies that at equilibrium the concentrations of nitrogen and oxygen will be significantly larger than that of nitric oxide.

Set up your ICE table like this

" " "N"_text(2(g]) " "+" " "O"_text(2(g]) " "rightleftharpoons" " color(red)(2)"NO"_text((g]) N2(g] + O2(g] 2NO(g]

color(purple)("I")" " " " "0" " " " " " " " " " " "0" " " " " " " " " " 0.500I 0 0 0.500
color(purple)("C")" "(+x)" " " " " "(+x)" " " " (0.500 - color(red)(2)x)C (+x) (+x) (0.5002x)
color(purple)("E")" " " "(x)" " " " " " " "(x)" " " " " "0.500 - color(red)(2)xE (x) (x) 0.5002x

By definition, the equilibrium constant for this reaction will be

K_c = (["NO"]^color(red)(2))/( ["N"_2] * ["O"_2]) = (0.500 - color(red)(2)x)^color(red)(2)/(x * x)Kc=[NO]2[N2][O2]=(0.5002x)2xx

K_c = (0.500 - color(red)(2)x)^color(red)(2)/x^2Kc=(0.5002x)2x2

Now, notice that you can take the square root of both sides to get

sqrt(K_c) = sqrt((0.500 - color(red)(2)x)^color(red)(2)/x^2)Kc=(0.5002x)2x2

sqrt(1.0 * 10^(-5)) = (0.500 - 2x)/x1.0105=0.5002xx

Rearrange this equation to solve for xx

sqrt(10^(-5)) * x = 0.500 - 2x105x=0.5002x

x * (2 + sqrt(10^(-5))) = 0.500x(2+105)=0.500

x = 0.500/(2 + sqrt(10^(-5))) ~~ 0.2499988x=0.5002+1050.2499988

Notice how small the equilibrium concentration of nitric oxide will be when compared with those of nitrogen and oxygen

["NO"] = 0.500 - 2 * 0.2499988= 2.4 * 10^(-6)"M"[NO]=0.50020.2499988=2.4106M

["N"_2] = ["O"_2] = x = "0.2499988 M" ~~ "0.25 M"[N2]=[O2]=x=0.2499988 M0.25 M

Practically, almost all of the nitric oxide will be converted to nitrogen and oxygen.

So remember, if you only start with products, the equilibrium will automatically shift to favor the formation of the reactants. Likewise, if you start with only reactants, the equilibrium will automatically shift to favor the formation of the products.

The magnitude of the shift will depend on the value of the equilibrium constant, K_cKc.