What is the mass produced of Hydrogen gas (H2), when 0.500g Hydrochloric acid (HCl) completely reacts to the following reaction. Zn + 2HCl → ZnCl2 + H2

Mass = 0.014 g

Explanation:

Given data:

Mass of HCl = 0.500 g

Mass of hydrogen gas produced = ?

Solution:

Chemical equation:

Zn + 2HCl       →      ZnCl₂ + H₂

Number of mole of HCl :

Number of moles = mass/molar mass

Number of moles = 0.500 g / 36.5 g/mol

Number of moles = 0.014 mol

Now we will compare the moles of HCl with hydrogen.

            HCl           :            H₂

              2             :            1

           0.014         :           1/2×0.014 = 0.007

Mass of hydrogen gas:

Mass = number of moles × molar mass

Mass =  0.007 mol × 2 g/mol

Mass = 0.014 g

answers: to make sure that all of the broken pieces of tablet were added to the water, to allow for fair comparison of all three trials, with different particle sizes to avoid experimental error