If 5.50 mol of HCl and 3.00 mol of O2 react according to the following equation, how many grams of water will form?

                    49.52 g of H₂O

Explanation:

                    The balance chemical equation for given reaction is as follow;

                                  4 HCl + O₂ → 2 H₂O + 2 Cl₂

Step 1: Find out Limiting reagent as;

According to balance equation,

                    4 moles of HCl reacted with  =  1 mole of O₂

So,

                5.50 moles of HCl will react with  =  X moles of O₂

Solving for X,

                     X =  5.50 mol × 1 mol / 4 mol

                     X =  1.375 moles of O₂

This means to completely consume 5.5 moles of HCl we will need 1.375 moles of O₂ while, we are provided with 3.0 moles of O₂ which is in excess hence, the limiting reagent in this problem is HCl and it will control the yield of products.

Step 2: Calculate Moles of H₂O produced;

According to balance equation,

                    4 moles of HCl produced  =  2 moles of H₂O

So,

                5.50 moles of HCl will react with  =  X moles of H₂O

Solving for X,

                     X =  5.50 mol × 2 mol / 4 mol

                     X =  2.75 moles of H₂O

Step 3: Calculate Mass of H₂O as;

                Mass  =  Moles × M.Mass

                Mass  =  2.75 mol × 18.01 g/mol

                Mass =  49.52 g of H₂O