What mass of Na2S is produced when 20g of sodium reacts with excess sulfur?

Answer 1

2Na + S ==> Na2S
mols Na = grams/atomic mass = ?
Using the coefficients in the balanced equation, convert mols Na to mols Na2S. That's ?mols Na x (1 mol Na2S/2 mols S)= ?mols Na x 1/2 = ?

Then grams Na2S = mols Na2S x molar mass Na2S

Answer 2

48.39 g Na2S