The answer is 10.23 moles.
Molecular weight of C3H8 via kwout
Molecular weight calculation (C₃H₈):
C = 12.0107*3 = 36.0321
H = 1.00794*8 = 8.06325
C₃H₈ = 44.1 g/mol
Divide 451 g by 44.1 g/mol = 10.23 moles.
Molecular formula C₃H₈ is known as propane. It is a colorless gas with a faint petroleum-like odor. It is shipped as a liquefied gas under its vapor pressure.
For transportation it may be stenched. Contact with the unconfined liquid can cause frostbite by evaporative cooling.
Easily ignited. The vapors are heavier than air and a flame can flash back to the source of leak very easily. The leak may be either a liquid or vapor leak. The vapors can asphyxiate by the displacement of air. Under prolonged exposure to fire or heat the containers may rupture violently and rocket.
More detailed infor about C₃H₈ can be found on pubhem.ncbi.nlm.nih.gov.
Tip! Learn three steps to converting grams of a substance to moles from ChemTeam.info.