Question

Calculate the mass of sodium oxide formed when 3.45 grams of sodium burns in air

Answer 1

NOTE: The problem, as stated, is worked below; however, if the sodium is burned is excess oxygen the primary product formed is sodium peroxide, Na2O2.

4Na + O2 ==> 2Na2O
mols Na = grams/molar mass = 3.45/23 = 0.15
mols Na2O formed = 0.15 moles Na x (2 mols Na2O/4 mols Na) = 0.15 x (1/2) = ?
Then grams Na2O = mols Na2O x molar mass Na2O = ?
Post your work if you get stuck.