
William W. answered 06/07/22
Math and science made easy - learn from a retired engineer
Using the balanced chemical reaction equation:
C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(g)
If you start with 27.3 g of C3H8(g), first convert this to the number of moles of C3H8(g) by dividing by the molar mass. The molar mass of C3H8 is calculated by using the atomic mass of carbon found in the Periodic Table (carbon = 12.011 g/mol) and the hydrogen (hydrogen = 1.008 g/mol) so the molar mass is (3)(12.011) + (8)(1.008) = 44.097 g/mol.
(27.3 g)/(44.097 g/mol) = 0.61909 moles of C3H8(g)
The chemical reaction equation says that for every 1 mole of C3H8(g) reacted, 4 moles of H2O(g) is produced. So the number of moles of H2O produced is (0.61909)(4) = 2.476 moles. Now use the molar mass of H2O to convert this to grams. The molar mass is (2)(1.008) + (1)(15.999) = 18.015 g/mol.
(2.476 mol)(18.015 g/mol) = 44.6 g H2O