if k=1.00x10^-4 for the reaction N2(g)+O2(g)_________ 2NO(g)find the number of moles of NO in a 10.0L container if the intial (N2)and (O2)is 1.00mol/L. pl i need this answer now thankyou

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doabbott3 eNotes educator| Certified Educator

Amazing.... I assume this answer is much too late; however, for posterity (and to prove myself?); here goes.... (I might mention that simply doing the problem for you may have very little impact on your learning to do it yourself; you should try, hard, to do as much as you can BEFORE you ask...?)

The general equilibrium equation constant, (1X10^-4) is equal to the mathematical product of the concentration of products [NO] , in mole/L, raised to the respective power of their coefficients, 2; Divided by the product of the concentrations of the reactants, [N2] & [O2] raised to the respective power of their coefficients:  

1X10^-4 = [NO]^2/ {[N2][O2]}

Initial Concentrations of N2 and O2 = 1M; NO= 0M

If X amount of N2 and O2 react then:

Equilibrium concentrations of N2 and O2 = [1-X]

Equilibrium concentration of NO = 2X

So since 1X10^-4 is small; not much reacts so "X" is gonna be small; therefore [1-X] =~1

Therefore: 1X10^-4 = [2X]^2 /{[1][1}

and 1X10^-4 = 4X^2 or 1X10^-4 /4 = X^2 or 25X 10^-6 = X^2 or 5X10^-3 = X so [NO] = 2X = [1X10^-2]