How much ko2 is needed to react with 75.0 l of carbon dioxide at - 25˚c and 215 kpa?

First, we convert the pressure in kPa to atm. That is,

(215 kPa) x (1 atm / 101.325 kPa) = 2.122 atm

Then, determine the amount of carbon (C) in mol by assuming that it is an ideal gas.

n = (2.122 atm) (75 L) / (0.0821 L. atm/mol. K) (-25 + 273.15)

n = 7.81 mols

The reaction is expressed as,

4KO2 + 2CO2 - - > 2K2CO3 + 3O2

From the equation,

(7.81 mols CO2) x (4 mols KO2/2 mols CO2) = 15.62 mols KO2