Answer:

Step-by-step explanation:
We will need a balanced chemical equation with masses and molar masses, so, let's gather all the information in one place.
MM: 142.04 233.29
Ba²⁺ + Na₂SO₄ ⟶ BaSO₄ + 2Na⁺
m/g: 27.4
(a) Moles of Na₂SO₄

(b) Moles of BaSO₄

(c) Mass of BaSO₄
