Question

find the mass of 10 moles of sodium sulphide (Na2S)

Answer 1

First we find the molar mass of Na2S

Molar mass = 2(Mass of Na) + (Mass of S)

= 2(23) + 32
= 46 + 32
= 78 g/mol

Thus, one mole Na2S has 78 g mass

So, 10 moles Na2S will have 780 gram mass.