Therefore, we get 1 mol of barium sulfate in its solid form, dissociates into 1 mol of barium plus 1 mol of sulfate, and both guys are in the Aqueous form. The first step is to write the KSP equation. To write the KSP equation, we simply realize that this guy is a solid and therefore he doesn't count. In this equation. These guys only count because they're both atreus. Remember, we never count solids and we never count liquids.