Question

If 3.5 moles of nitrogen monoxide (NO) react with 6.0 moles of oxygen gas (O2), how many moles of the product can be formed and how many moles of the excess reactant will be left over when the reaction is complete? Show all of your work. unbalanced equation: NO + O2 “yields”/ NO2

Answer 1

Answer: -

4.25 mol of O₂ left as excess.

3.5 mol of NO₂ formed.

Explanation: -

Number of moles of NO taken = 3.5

Number of moles of O₂ taken = 6.0

The balanced chemical equation for this reaction is

2 NO+ O₂ → 2 NO₂

From the equation we can see that

2 mol of NO react with 1 mol of O₂

3.5 mol of NO react with $\frac{1 mol O2}{2 mol NO}$ x 3.5 mol NO

= 1.75 mol O₂

So Oxygen O₂ is in excess and NO is the limiting reagent.

Moles of O₂ left over = 6 - 1.75 =4.25 mol of O₂

From the balanced chemical equation we see

2 mol of NO gives 2 mol of NO₂

3.5 mol of NO gives$\frac2 mol NO2}{2 mol NO}$ x 3.5 mol NO

= 3.5 mol of NO₂