- #1

skepticwulf

- 74

- 1

## Homework Statement

Ammonia reacts with O2 to form either NO(g) or NO2(g) according to these unbalanced equations:

NH3 + O2 ----> NO + H2O

NH3 + O2 ----> NO2 + H2O

In a certain experiment 2.00 moles of NH3 and 10.00 moles

of O2 are contained in a closed flask. After the reaction is

complete, 6.75 moles of O2 remains. Calculate the number

of moles of NO in the product mixture: (Hint: You cannot

do this problem by adding the balanced equations because you

cannot assume that the two reactions will occur with equal

probability.)

## Homework Equations

## The Attempt at a Solution

After the balance of equations,

x=mol of NH3 in the first equations(=mol of NO as well)

1st reaction:

2 mol NH3 gives 5/2 mole O2

x mol gives ... 5x/4 mole O2

2nd reaction:

2 mol NH3 gives 7/2 mole O2

(2-x) mol gives ... 7(2-x)/4 mole O2

5x/4 + 7(2-x)/4 + 6.75=10

I find: x=0.5 mole of NH3 as well as 0.5 mole of NO

But solution manual has 0.48 as answer, is my calculation wrong in any way??