# Identify the limiting and excess reagents in this case. Justify your predictions.  NO2 + O2 --> NO + O3 The chemical equation for this reaction is; NO2 + O2 --> NO + O3 In a given reaction, 5.20g of nitrogen dioxide and 3.90g of oxygen react.  a) Identify the limiting and excess reagents in this case. Justify your predictions.  b) What mass of ozone is expected?

At standard temperature and pressure we know that the volume of one mole of any gas is 22.4 liters.  So if we convert the mass of each gas from grams to moles, the larger one will be the one in excess.

5.2 g NO2 (mole/46 g) = 0.113 mole NO2

...

## Unlock This Answer Now

Start your 48-hour free trial to unlock this answer and thousands more. Enjoy eNotes ad-free and cancel anytime.

At standard temperature and pressure we know that the volume of one mole of any gas is 22.4 liters.  So if we convert the mass of each gas from grams to moles, the larger one will be the one in excess.

5.2 g NO2 (mole/46 g) = 0.113 mole NO2

3.9 g O2 (mole/32 g) = 0.122 mole O2

Since 0.122 > 0.113 and both reactants are consumed in a 1:1 ratio, NO2 is the limiting reagent and O2 is the excess reagent.

To determine the mass of ozone (O3) produced, assume that the entire mass of the limiting reagent is consumed to produce O3.  This means that the 0.113 moles of NO2 will be converted to 0.113 moles of O3.  Now convert to grams.

0.113 mole O3 (48 g/mole) = 5.42 grams O3

5.42 grams of O3 will be produced.

Approved by eNotes Editorial Team