What is 736.9x10^5 in standard form

Mass of gas = 0.33 g

Explanation:

Given data:

Mass of magnesium = 23 g

Mass of HCl = 12 g

Mass of MgCl₂ produced = 30 g

Mass of hydrogen gas produced = ?

Solution;

Chemical equation:

Mg + 2HCl    →  MgCl₂ + H₂

Number of moles of Mg:

Number  of moles = mass/molar mass

Number  of moles = 23 g/ 24 g/mol

Number of moles = 0.96 mol

Number of moles of HCl:

Number  of moles = mass/molar mass

Number  of moles = 12 g/ 36.5 g/mol

Number of moles = 0.33 mol

Now we will compare the moles of Hydrogen gas with both reactant.

                                Mg            :          H₂

                                  1              :          1

                                 0.96        :        0.96

                                HCl           :           H₂

                                   2            :            1

                               0.33           :        1/2×.33= 0.165 mol

The number of moles of hydrogen gas produced by HCl are less so it will limiting reactant and limit the yield of gas,.

Mass of H₂:

Mass = number of moles × molar mass

Mass =  0.165 mol × 2 g/mol

Mass = 0.33 g