Question

What mass of sodium oxide could be obtained by burning 11.5g of sodium in air

Answer 1

The mass of sodium oxide could be obtained by burning 11.5g of sodium in air :-

4Na + O2 → 2Na2O

n(Na) = m/M = 11.5g/23g/mol = 0.5 mol

n(Na2O) = n(Na)/2 = 0.5/2 = 0.25 mol

M(Na2O) = 23*2 + 16 = 62 g/mol

m(Na2O) = n*M = 0.5mol*62g/mol = 15.5 g

so, the mass of sodium oxide is equal to 15.5 grams.