Question

If you start with 4.00 moles of C3H8 (propane) and 4.00 moles of O2, how many moles of carbon dioxide can be produced?

Answer 1

 C3H8 + 5 O2 = 3 CO2 + 4H2O

1 mole C3H8 ----------- 5 moles O2 ---------- 3 moles CO2
4.00 moles C3H8 ----- 4.00 moles O2 ------ ( moles CO2)

moles CO2 = 4.00 x 3 / 5

moles  CO2 = 12 / 5

= 2.40 moles of CO2

hope this helps!