Write the chemical equation and balance ! aluminum phosphate and nickel (ii) sulfide react to form aluminum sulfide and nickel (ii) phosphate.

You can start by writing out the molecular formula of each molecule.

Aluminum (Al 3+) Phosphate (PO4 3-)

AlPO4

Nickel II (Ni 2+) sulfide (S 2-)

NiS

Aluminum Sulfide

Al2S3

Nickel Phosphate

Ni3(PO4)2

If you’re wondering, we get those charges by looking at the periodic table. The metals usually have a + charge based on their group number. The nonmetals usually - charge egual to 8 - their group number.

You then balance the ions by flipping the charges, dropping the signs, and adding them in as subscripts.

Now we can put it into an equation

AlPO4 + NiS —-> Al2S3 + Ni3(PO4)2

Balance by adding coefficients

2 AlPO4 + 3 NiS —-> Al2S3 + Ni3(PO4)2