What mass of carbon dioxide (in ) is produced upon the complete combustion of 18.9 of propane (approximate contents of one 5-gallon tank)?

What mass of carbon dioxide (in ) is produced upon the complete combustion of 18.9 of propane (approximate contents of one 5-gallon tank)? Assume that the density of the liquid propane in the tank is 0.621 . (: Begin by writing a balanced equation for the combustion reaction.)