The combustion of propane may be described by the chemical equation C 3 H 8 ( g ) + 5 O 2 ( g ) ⟶ 3 CO 2 ( g ) + 4 H 2 O ( g ) C3H8(g)+5O2(g)⟶3CO2(g)+4H2O(g) How many grams of O 2 ( g ) O2(g) are needed to completely burn 19.7 g C 3 H 8 ( g ) ?

72 grams of are needed to completely burn 19.7 g

Explanation:

According to avogadro's law, 1 mole of every substance weighs equal to molecular mass and contains avogadro's number of particles.

To calculate the number of moles, we use the equation:

Putting in the values we get:

According to stoichiometry:

1 mole of requires 5 moles of oxygen

0.45 moles of require= moles of oxygen

Mass of

72 grams of are needed to completely burn 19.7 g