Answer:
3*0.35L = 1.05L
Step-by-step explanation:
For part A, we need the ratio of moles of propane to moles of oxygen to get the volume of oxygen required. 
 
The equation tells us there are 5 moles of oxygen gas required to combust 1 mole of propane. 
 
So the required volume of oxygen is 5*0.35L = 1.75L
 
The equation also tells us that 3 moles of carbon dioxide are produced from the combustion of one mole of propane. 
 
Therefore the produced volume of carbon dioxide is 3*0.35L = 1.05L