Question

Propane gas, C3H8, undergoes combustion with oxygen gas to produce carbon dioxide and water gases. Propane has a density of 2.02 g/L at room temperature.

Write the balanced chemical equation.

How many grams of H2O form when 5.50 L of C3H8 reacts?

How many grams of H2O can be produced from the reaction of 170. g of C3H8 ?

Answer 1

Ans :

The balanced chemical equation is given as :

C3H8 + 5O2 = 3CO2 + 4H2O

Density = mass / volume

2.02 = m / 5.50

m = 11.11 g

Number of mol of propane = 11.11 / 44.09562 = 0.252 mol

Each mol propane makes 4 mol water

So number of mol of water produced = 0.252 x 4 = 1.008 mol

Mass of H2O formed = 1.008 x 18.01528

= 18.2 grams

Number of mol of propane = given mass / molar mass

= 170 / 44.09562

= 3.855 mol

Each mol propane makes 4 mol water

So number of moles of H2O = 4 x 3.855 = 15.42 mol

Mass of H2O formed = 15.42 x 18.01528

= 277.8 grams