Exercise 3 | The periodic table and Chemical Periodicity

The unbalanced chemical equation of the combustion of octane is:

C8H18 (l) + O2 (g) → CO2 (g) + H2O (l)

Balance the equation.

What mass of O2 will be needed to burn 50.8 g of octane?

How many moles of water are produced?

2 C8H18 (l) + 25 O2 (g) →  16 CO2 (g) + 18 H2O (l)
 

According to the stoechiometry of the balanced equation:
nC8H182 = nO225  ⇒ mO2MO2 = 252 x mC8H18MC8H18

mO2 = 178 g
 

nC8H182 = nH2O18 ⇒  nH2O 182 x mC8H18MC8H18
nH2O = 4.01 mol