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?

a) 0.018

b) 0.034

c) 0.045

d) 0.091

Answer 1

0.091 g O2 is the correct answer

Answer 2

The balanced chemical reaction will be:

C3H8 + 5O2 = 3CO2 +4H2O

We are given the amount of propane gas to be burned. This will be our starting point.

0.025 g C3H8 ( 1 mol C3H8 / 44.1 g C3H8 ) ( 5 mol O2/1 mol C3H8)(32 g O2 / 1 mol O2) = 0.09 g O2