If a solution of sodium phosphate, Na3PO4, is poured into seawater, precipitates of calcium phosphate and magnesium phosphate are formed. (Magnesium and calcium ions are among the principle ions found in seawater.) Write net ionic reactions for the reactions. Include physical states in your answers.

Formation of calcium phosphate

Formation of magnesium phosphate

3Ca^2+(aq) + 2PO4^3-(aq) ==> Ca3(PO4)2(s)

Mg3(PO4)2 is done the same way.

To write the net ionic reactions for the formation of calcium phosphate and magnesium phosphate when sodium phosphate is poured into seawater, we need to first identify the equations for the reactions involving the sodium phosphate and the respective calcium and magnesium ions.

1. Formation of Calcium Phosphate:

The chemical equation representing the reaction between sodium phosphate (Na3PO4) and calcium ions (Ca2+) can be written as:

3 Ca2+ + 2 PO43- → Ca3(PO4)2

This equation is not balanced in terms of charge, as the calcium ions have a +2 charge each, whereas the phosphate ions (PO43-) collectively carry a -3 charge. To balance the charges, we need to multiply the number of calcium ions by 2 and the number of phosphate ions by 3:

6 Ca2+ + 3 PO43- → Ca3(PO4)2

The net ionic equation takes into account only the ions directly involved in the reaction, which are the calcium (Ca2+) and phosphate (PO43-) ions. The sodium ions (Na+) do not participate in the precipitation reaction; therefore, they are spectator ions. The net ionic equation is:

6 Ca2+ + 3 PO43- → Ca3(PO4)2(s)

The "(s)" represents the solid precipitate of calcium phosphate formed.

2. Formation of Magnesium Phosphate:

Similarly, the chemical equation for the reaction between sodium phosphate (Na3PO4) and magnesium ions (Mg2+) can be written as:

3 Mg2+ + 2 PO43- → Mg3(PO4)2

To balance the charges, we multiply the number of magnesium ions by 2:

6 Mg2+ + 3 PO43- → Mg3(PO4)2

The net ionic equation includes only the magnesium (Mg2+) and phosphate (PO43-) ions and excludes the sodium ions (Na+), which are spectator ions:

6 Mg2+ + 3 PO43- → Mg3(PO4)2(s)

Once again, the "(s)" denotes the solid precipitate of magnesium phosphate formed.