My teacher uses the online homework ARIS and the question is write the balanced equation of Mn3(PO4)2: i have enter the answer Mn3(PO4)2 (s) =3Mn^2+(aq) + 2(PO4)^3-(aq)

This looks ok to me IF it is for the solubility of Mn3(PO4)2 in water. I suppose the reason you posted is to tell us this isn't the right answer (at least I've seen that before in the last few days). If it isn't, please let us know what ARIS thinks.

To write the balanced equation for Mn3(PO4)2, you need to determine the correct coefficients for each compound involved. Here's how you can do it step by step:

1. Start by breaking down the formula Mn3(PO4)2 into its individual ions:
Mn^2+ + PO4^3-

2. Next, you need to determine the number of each ion on both sides of the equation. Since the formula Mn3(PO4)2 indicates that there are three manganese ions (Mn^2+) and two phosphate ions (PO4^3-), you need to include these quantities in the balanced equation.

3. Now, write the balanced equation using the coefficients determined in step 2:
Mn3(PO4)2 (s) → 3 Mn^2+(aq) + 2 (PO4)^3-(aq)

By following these steps, you will have the correct balanced equation for Mn3(PO4)2.