0.975 g of H₂
The equation for the reaction between magnesium and HCl is given by;
Mg + 2HCl --> MgCl2 + H2
We are given 35.2 g of of HCl reacted with excess magnesium.
We are required to calculate the amount of Hydrogen produced;
Step 1: Calculation of number of moles of HCl
To calculate the number of moles we divide the mass by the molar mass
Molar mass of HCl= 36.46 g/mol
Mass of HCl = 35.2 g
Number of moles = 35.2 g ÷ 36.46 g/mol
= 0.965 moles
Step 2: Moles of Hydrogen produced
From the equation, the mole ratio of HCl to H₂ is 2 : 1
Therefore; Moles of Hydrogen = Moles of HCl ÷ 2
= 0.965 moles ÷ 2
= 0.4825 moles
Step 3: Mass of hydrogen gas produced
Mass is calculated by multiplying the number of moles by the molar mass.
Molar mass of hydrogen =2.02 g/mol
Moles of hydrogen = 0.4825 moles
Mass of Hydrogen = 0.4825 moles × 2.02 g/mol
= 0.97465
= 0.975 g
Therefore; 0.975 g of hydrogen will be produced.
