According to the chemical equation

4KO_2(s) + 2CO_2(g) ---> 2K₂CO_3(s) + 3O_2(g)

d) how many formula units of potassium superoxide must react to form 27 molecules of O₂ assuming excess carbon dioxide?

Answer

According to the balanced chemical equation when three molecules of dioxygen are formed when 4 formula units of potassium superoxide react (assuming excess carbon dioxide). Dioxygen and potassium superoxide always combine in this ratio according to this equation. We can use this relationship as a unit conversion factor to convert between potassium superoxide and dioxygen.

This conversion between dioxygen and potassium superoxide tells us the thirty six formula units of potassium superoxide are formed when twenty seven molecules of dioxygen react.