C3H8 + 5O2 → 3CO2 + 4H2O

What is the mass of O2 needed to produce 31.0 moles of H2O?
(2step)

m= 1240 g O2

Explanation: We will do stoichiometry for this problem to solve for the mass of O2 in grams.

First step is to convert the moles of H2O to moles of O2 using their mole ratio.

31.0 moles H2O x 5 moles O2 / 4 moles H2O

= 38.75 moles O2

Next is to convert the moles of O2 to mass using the molar mass of O2.

38.75 moles O2 x 32 g O2 / 1 mole O2 = 1,240 g O2

d

explanation: