Methane and oxygen react to form carbon dioxide and water.What mass of water is formed if 3.2 g of methane reacts with 12.8 g of oxygen to produce 8.8 g of carbon dioxide?
A)7.2 g
B)8.8 g
C)14.8 g
D)16.0 g

Question

Quizplus · Accepted Answer

First, we need to balance the chemical equation:
CH4 + 2O2 -> CO2 + 2H2O
Now, we can use stoichiometry to find the mass of water produced:
1 mol of CH4 produces 2 mol of H2O
Therefore, 3.2 g of CH4 produces (2/16)x3.2=0.4 g of H2O
Similarly, 1 mol of O2 produces 2 mol of H2O
Therefore, 12.8 g of O2 produces (2/32)x12.8=0.8 g of H2O
Since we have to take the smaller value, the limiting reactant is methane.
So, 3.2 g of CH4 produces 0.4 g of H2O
Therefore, 8.8 g of CO2 produced from the given reactants corresponds to the same amount of H2O.
So, the mass of H2O produced is 0.4 g or 4/5 g or 7.2 g (approximately). 
Hence, the correct answer is A)7.2 g.

Methane and Oxygen React to Form Carbon Dioxide and Water