Question

The flame of the Bunsen burner is caused by the reaction of methane (CH₄) and oxygen according to the the following unbalanced equation

CH₄ + O₂ → CO₂ + H₂O

If 5.00 g of methane is burned, what mass of water can be produced? Assume the reaction goes to completion.

Answer 1

The balanced chemical reaction is:

CH4 + 2 O2 —> CO2 + 2 H2O

Molar mass of CH4 = 1*MM(C) + 4*MM(H)

= 1*12.01 + 4*1.008

= 16.042 g/mol

mass of CH4 = 5 g

mol of CH4 = (mass)/(molar mass)

= 5/16.042

= 0.3117 mol

From balanced chemical reaction, we see that

when 1 mol of CH4 reacts, 2 mol of H2O is formed

mol of H2O formed = (2/1)* moles of CH4

= (2/1)*0.3117

= 0.6234 mol

mass of H2O = number of mol * molar mass

= 0.6234*18.016

= 11.2 g

Answer: 11.2 g