Find the number of grams of HCl needed to react completely with .50 moles of magnesium. Mg(s) + 2HCl(aq) --> MgCl2(aq) + H2(g)

                      36.46 g of HCl

Explanation:

                    The balance chemical equation for given single replacement reaction is as follow;

                              Mg + 2 HCl → MgC₂ + H₂

Step 1: Calculate Moles of HCl required:

According to equation,

                   1 mole of Mg reacted with  =  2 moles of HCl

So,

                0.5 moles of Mg will react with  =  X moles of HCl

Solving for X,

                     X =  0.5 mol × 2 mol / 1 mol

                      X =  1 mol of HCl

Step 2: Calculate Mass of HCl as;

                    Moles  =  Mass / M.Mass

Or,

                    Mass  =  Moles × M.Mass

                    Mass  =  1 mol × 36.46 g/mol

                   Mass =  36.46 g of HCl