The molar mass of oxygen gas (O2) is 32.00 g/mol.
The molar mass of C3H8 is 44.1 g/mol.
This kind of reaction is a combustion:
C3H8 + 5O2 → 3CO2 + 4H2O (In a combustion we obtain CO2 and H2O. Don't forget to balance this equation)
Procedure:
Let's use stoichiometry to solve this
44.1 g C3H8 --------- 5 x 32.00 g O2
0.025 g C3H8 --------- X
X = 0.091 g O2
Answer: mass of O2 required = 0.091 g