Your reaction will produce
First, start with the balanced chemical equation for the combustion of propane
In other words, regardless of how many moles of propane react, you'll always have 3 times more moles of carbond ioxide produced.
Now, in order to determine how many moles of propane rected, you must use the ideal gas law equation,
SIDE NOTE If you want to use the value of R = 0.082, expressed in atm L/mol K, do not forget to transform the pressure from kPa to atm and the temperature from Celsius to Kelvin.
Since you know how many moles of propane reacted, you automatically know - the mole ratio tells you - how many moles of carbond sioxide were produced