Answer: Theoretical mass of sodium sulphate (
) is 514.118 grams.
Step-by-step explanation: For a given reaction,

As NaOH is used in excess, therefore it is an excess reagent and
is a limiting reagent as the quantity of the product will depend on it.
We are given 355 grams of
.
Molar mass of
= 98.079 g/mol
Molar mass of
= 142.04 g/mol
1 mole of
is producing 1 mole of
, so
98.079 g/mol of
will produce 142.04 g/mol of
355 grams of
will produce =
of

Mass of
= 514.118 grams