Question

Calculate the mass of water produced when 42.0 g of propane, c3h8, is burned with 115 g of oxygen. hint: write balanced equation first

Answer 1

51.75 g of H₂O

Solution:

The balance chemical equation is as follow,

C₃H₈ + 5 O₂ → 3 CO₂ + 4 H₂O

Step 1: Finding Limiting Reagent:

According to equation,

44.1 g (1 mol) C₃H₈ reacts with = 160 g (5 mol) of O₂

So,

42 g C₃H₈ will react with = X g of O₂

Solving for X,

X = (42 g × 160 g) ÷ 44.1 g

X = 152.38 g of O₂

As we are only provided with 115 g of O₂, Hence it is the limiting reactant and it will control the yield of products.

Step 2: Calculating amount of H₂O:

According to equation,

160 g (5 mol) O₂ produces = 72 g (4 mol) of H₂O

So,

115 g O₂ will produce = X g of H₂O

Solving for X,

X = (72 g × 115 g) ÷ 160 g

X = 51.75 g of H₂O