1. Barium Hydroxide and Ammonium Sulfate

* Reactants:

* Barium hydroxide: Ba(OH)₂

* Ammonium sulfate: (NH₄)₂SO₄

* Products:

* Barium sulfate: BaSO₄ (insoluble, forms a precipitate)

* Ammonium hydroxide: NH₄OH (weak base, decomposes into ammonia and water)

* Balanced Equation:

Ba(OH)₂(aq) + (NH₄)₂SO₄(aq) → BaSO₄(s) + 2NH₄OH(aq)

2. Potassium Phosphate and Calcium Chloride

* Reactants:

* Potassium phosphate: K₃PO₄

* Calcium chloride: CaCl₂

* Products:

* Calcium phosphate: Ca₃(PO₄)₂ (insoluble, forms a precipitate)

* Potassium chloride: KCl (soluble)

* Balanced Equation:

2K₃PO₄(aq) + 3CaCl₂(aq) → Ca₃(PO₄)₂(s) + 6KCl(aq)

Key Points:

* (aq) indicates the substance is dissolved in water (aqueous solution).

* (s) indicates a solid precipitate.

* The coefficients in front of each compound ensure the number of atoms of each element is the same on both sides of the equation (mass conservation).