If 100.0 grams of C3H8 burns, how many moles of 3CO2 will form?

Answer 1

Start with the balanced equation:

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

First step is to convert grams to moles...this is usually a good first step

There are several ways to do this.. ratios is one way

100g C3H8 / x mols = 44.089g / 1mol

x = 2.27 moles

The balanced equation relates moles of reactants and products, so

1 mol C3H8 produces 3 moles CO2

you can use this relationship to set up a ratio with your known (given moles C3H8) and your unknown (moles CO2)

1 mol C3H8 / 3 mol CO2 = 2.27 moles C3H8 / x mole CO2

x = 6.81 moles CO2