Question

A sample of 1.05 moles of propane (C3H8) is completely burned in 2.25 moles of oxygen. The products are carbon dioxide and water.

Answer 1

C3H8 + 5O2 --------------> 3CO2 + 4H2O

1 mole of C3H8 react with 5 moles of O2

1.05 moles of C3H8 react with = 5*1.05/1   = 5.25 moles of O2

O2 is limiting reactant

C3H8 + 5O2 --------------> 3CO2 + 4H2O

5 moles of O2 react with C3H8 to gives 3 moles of CO2

2.25 moles of O2 react with C3H8 to gives = 3*2.25/5   = 1.35 moles of CO2

5 moles of O2 react with C3H8 to gives 4 moles of H2O

2.25 moles of O2 react with C3H8 to gives = 4*2.25/5   = 1.8 moles of H2O