Question

The chemical equation below shows the combustion of propane (C3H8). C3H8 + 5O2 mc012-1.jpg 3CO2 + 4H2O The molar mass of oxygen gas (O2) is 32.00 g/mol. The molar mass of C3H8 is 44.1 g/mol. What mass of O2, in grams, is required to completely react with 0.025 g C3H8? 0.018 0.034 0.045 0.091

Answer 1

The mass of O2 required to completely react with 0.025g C3H8 is calculated as follows

C3H8 + 5O2 = 3CO2 + 4H2o

calculate the moles of C3H8 that is moles=mass/molar mass
= 0.025g / 44.1 g/mol= 5.669 x10^-4 moles

by use of mole ratio from reacting equation between C3H8 to O2 which is 1:5 the moles of O2 = 5 x (5.669 x10^-4) = 2.83 x10^-3 moles

mass of O2 = moles x molar mass
= (2.83 x10^-3)moles x 32 g/mol = 0.091 g ( answer D)