Answer: A. 14.00
Explanation:
Looking at the given balanced equation for the combustion of Propane
C3H8 + 5 O2 -----> 3 CO2 + 4H20
1 mole of Propane produces 4 moles of water vapor.
∴ 3.50 moles of Propane would have an equation such as this, when the coefficients is multiplied by 3.50
3.5 C3H8 + 17.5 O2 -------> 10.5 CO2 + 14 H2O
This imply that 14 moles of water vapor is produced by the combustion of 3.50 moles of Propane