What is the net ionic equations for:

1. Arsenic(III) iodide + Sodium sulfide

2. Lead(II) nitrate + Ammonium oxalate

3. Magnesium chromate + Copper(II) sulfate

Pb^2+ + C2O4^2- ==> PbC2O4

CrO4^2- + Cu^2+ ==> CuCrO4
As^3+ + S^2- ==> As2S3 you balanced

To determine the net ionic equations for these reactions, we need to first write out the balanced molecular equations, followed by the ionic equations, and finally determine the net ionic equations by canceling out spectator ions.

1. Arsenic(III) iodide + Sodium sulfide

The balanced molecular equation is:
AsI3 + 3Na2S → As2S3 + 6NaI

To write the ionic equation, we break apart the soluble ionic compounds into their respective ions:
AsI3(s) + 3Na2S(aq) → As2S3(s) + 6NaI(aq)

Next, we separate the strong electrolytes into ions:
As3+(aq) + 3I^-(aq) + 6Na+(aq) + 3S^2-(aq) → As2S3(s) + 6Na+(aq) + 6I^-(aq)

Finally, we cancel out the spectator ions, which are the ions that appear on both sides of the equation:
As3+(aq) + 3I^-(aq) + 3S^2-(aq) → As2S3(s)

The net ionic equation is:
As3+(aq) + 3I^-(aq) + 3S^2-(aq) → As2S3(s)

2. Lead(II) nitrate + Ammonium oxalate

The balanced molecular equation is:
Pb(NO3)2 + (NH4)2C2O4 → PbC2O4 + 2NH4NO3

To write the ionic equation, we break apart the soluble ionic compounds into their respective ions:
Pb(NO3)2(aq) + (NH4)2C2O4(aq) → PbC2O4(s) + 2NH4NO3(aq)

Next, we separate the strong electrolytes into ions:
Pb2+(aq) + 2NO3^-(aq) + 2NH4+(aq) + C2O4^2-(aq) → PbC2O4(s) + 2NH4+(aq) + 2NO3^-(aq)

Finally, we cancel out the spectator ions:
Pb2+(aq) + C2O4^2-(aq) → PbC2O4(s)

The net ionic equation is:
Pb2+(aq) + C2O4^2-(aq) → PbC2O4(s)

3. Magnesium chromate + Copper(II) sulfate

The balanced molecular equation is:
MgCrO4 + CuSO4 → MgSO4 + CuCrO4

To write the ionic equation, we break apart the soluble ionic compounds into their respective ions:
MgCrO4(aq) + CuSO4(aq) → MgSO4(aq) + CuCrO4(s)

Next, we separate the strong electrolytes into ions:
Mg^2+(aq) + CrO4^2-(aq) + Cu^2+(aq) + SO4^2-(aq) → Mg^2+(aq) + SO4^2-(aq) + CuCrO4(s)

Finally, we cancel out the spectator ions:
CrO4^2-(aq) + Cu^2+(aq) → CuCrO4(s)

The net ionic equation is:
CrO4^2-(aq) + Cu^2+(aq) → CuCrO4(s)

In summary:
1. Arsenic(III) iodide + Sodium sulfide:
Net ionic equation: As3+(aq) + 3I^-(aq) + 3S^2-(aq) → As2S3(s)

2. Lead(II) nitrate + Ammonium oxalate:
Net ionic equation: Pb2+(aq) + C2O4^2-(aq) → PbC2O4(s)

3. Magnesium chromate + Copper(II) sulfate:
Net ionic equation: CrO4^2-(aq) + Cu^2+(aq) → CuCrO4(s)