If 38.7 grams of lithium chlorate decomposes, how many grams of oxygen gas can be produced?

The formula for lithium chlorate is: 2LiClO₃ → 2LiCl + 3O₂

If moles = mass : molar mass

then moles of LiClO₃ = 38.7 g : [ (7 * 1) + (35.5 * 1) + (16 * 3) ] g/mol

= 38.7 g : (90.5 g) g/mol

= 0.428 mol

Now the mole ratio of LiClO₃ : O₂ is 2 : 3

∴ if moles of LiClO₃ = 0.428 mol

then moles of O₂ = (0.428 mol : 2) * 3

= 0.642 mol

Now since mass = moles * molar mass

∴ the mass of oxygen produced = 0.642 mol * (16 * 2) g/mol

= 20.544 g

∴ the grams of oxygen gas produced when 38.7 grams of lithium chlorate is decomposed is ~ 20.54 g.