According to the following reaction, how many grams of oxygen gas are necessary to form 0.289 moles carbon dioxide?

Question

propane (C₃H₈) (g) + oxygen (g) carbon dioxide (g) + water (g)

Answer 1

Hi, Akasia,

Balance the chemical equation first. That will tell you how many moles of oxygen are required to make one mole of CO2. Once you know that relationship, you can use that factor to determine the number of moles needed for the amount of CO2 specified.

Note that 5 moles of O2 are needed to make 3 moles of CO2. That ratio (1.667) needs to be multiplied by the number of moles of CO2, using the conversion factor (5molesO2)/(3moles CO2). 3 sig figs is needed for the answer of 0.482 grams.

Bob

Answer 2

C₃H₈ + 5O₂ ==> 3CO₂ + 4H₂O ... balanced equation

Using dimensional analysis we have...

0.289 mol CO₂ x 5 mol O₂ / 3 mol CO₂ x 32 g O₂/mol O₂ = 15.4 g O₂