Question

Determine the mass of oxygen necessary to react with 2.3 moles of HCl

Answer 1

4HCl + O₂  →  2Cl₂  +  2H₂O

mole ratio of HCl  :  O₂  is   4  :  1

∴ if moles of HCl = 2.3 mol

then mol of O₂ =  2.3 mol  ÷  4
                        = 0.575 mol

mass of O₂  =  moles of O₂ × molar mass of O₂
                    =  0.575 mol ×  (16 × 2) g/mol
                    =  18.4 g