Q 7. What is the mass of—
(c) 10 moles of sodium sulphite (Na2SO3 )?
The molecular mass of Sodium sulphite (Na2SO3 ) = 2 * 23 + 32 + 3 * 16
= 126u
Mass of 10 moles of sodium sulphite = 10 x Mass of 1 mole of Na2SO3
= 10 x molecular mass of Na2SO3 in grams
= 10 x 126 g
= 1260 g.