In the commercial manufacture of nitric acid, how many liters of nitrogen dioxide will produce 30 liters of nitric oxide given that both gases are at stp?
3no2 + h2o 2hno3 +no
a) 20 liters
b) 0.1 liters
c) 40 liters
d) 90 liters
e) 1.01 liters

At STP (standard pressure and temperature) each mole of gas occupies a volume of 22.4 liters.

The balanced chemical reaction tells you that 3 moles of nitrogen dioxide produce 1 mol of nitric oxide (both gases as per problem specifications).

3 moles * 22.4 = 67.2 liters

1 moles * 22.4 liters = 22.4

Ratio: 67.2 liters of nitrogen dioxide / 22.4 liters of nitric oxide = x liters of nitrogen dioxide / 30 liters of nitric oxide

Solve for x: x = 30 liters of nitric oxyde * 67.2 liters of nitriogen dioxide / 22.4 liters of nitric oxide = 90 liters oxide.nitrogen dioxide.