Define combustion of octane and a component of gasoline

 

Problem- Question: The complete combustion of octane, C8H18, a component of gasoline, proceeds as follows: 2C8H18(l)+25O2(g)?16CO2(g)+18H2O(g)

Part 1) How many moles of O2 are needed to burn 1.55mol of C8H18?

Part 2) How many grams of O2 are needed to burn 12.0g of C8H18?

Part 3) Octane has a density of 0.692 g/mL at 20 ?C. How many grams of O2 are required to burn 19.0gal of C8H18?

Hello Experts please provide me the detailed computation for above question