2H2 + O2 -> 2H20
What is the mass of water that is produced from 4.00 moles of oxygen gas reacting with hydrogen
gas?

                    144.08 g of H₂O

Explanation:

                     The balance chemical equation for the synthesis of water is as follow;

                                           2 H₂ + O₂ → 2 H₂O

Step 1: Find out moles of H₂O produced as;

According to balance chemical equation,

                    1 mole of O₂ produced  =  2 moles of H₂O

So,

                 4 moles of O₂ will produce  =  X moles of H₂O

Solving for X,

                    X =  4 mol × 2 mol / 1 mol

                    X  =  8 moles of H₂O

Step 2: Calculate Mass of H₂O as;

                 Mass  =  Moles × M.Mass

                 Mass  =  8 mol × 18.01 g/mol

                 Mass  = 144.08 g of H₂O