11. how many grams of o2 are required to produce 36.9 grams of zno?
22n +102 → 2zno

Mass = 7.2 g

Explanation:

Given data:

Mass of ZnO = 36.9 g

Mass of oxygen needed = ?

Solution:

Chemical equation:

2Zn + O₂ → 2ZnO

Number of moles of ZnO:

Number of moles = Mass/ molar mass

Number of moles = 36.9 g/81.38 g/mol

Number of moles = 0.45 mol

Now we will compare the moles of ZnO with oxygen:

                      ZnO           :           O₂

                         2             :            1

                      0.45           :       1/2 × 0.45 = 0.225

Mass of oxygen:

Mass = number of moles × molar mass

Mass = 0.225 mol × 32 g/mol

Mass = 7.2 g