C I. Group IA compounds are soluble. Ammonium compounds are soluble. Compounds containing hydroxide are usually insoluble. The exceptions are group IA metal hydroxides and the barium hydroxide.
Calcium hydroxide is slightly soluble.
V. Compounds containing chlorides, bromides, or iodides are usually soluble. Most sulfates are soluble. Know the difference between empirical and molecular formulas. Know how NH3 works as a weak base. Be able to balance redox equations.