Question

Suppose 3.68g of zinc was allowed to react with hydrochloric acid to produce zinc chloride and hydrogen gas. How much zinc chloride should you get? Suppose that you actually recovered 7.12g of zinc chloride. What is your percent yield?

Answer 1

Answer:

Percent yield = 86.2%

Explanation:

Given data:

Mass of zinc = 3.68 g

Mass of zinc chloride = ?

Percent yield = ?

Actual yield = 7.12 g

Solution:

Chemical equation:

Zn + 2HCl  → ZnCl₂  + H₂

Number of moles of zinc:

Number of moles  = Mass /molar mass

Number of moles = 3.68 g / 65.38 g/mol

Number of moles  = 0.06 mol

Now we will compare the moles of ZnCl₂ with zinc.

                 Zn            :               ZnCl₂

                  1               :               1

                 0.06           :            0.06

Theoretical yield of zinc chloride:        

Mass of ZnCl₂ = moles × molar mass

Mass of ZnCl₂ = 0.06 mol × 136.286 g/mol

Mass of ZnCl₂ =  8.2 g

Percent yield:

Percent yield = actual yield / theoretical yield × 100

Percent yield = 7.12 g/ 8.2 g × 100

Percent yield = 86.2%