1. The problem lists several chemical compounds: H₂O, H₂S, NH₃, PH₃, HF, HCl, CH₄, H₂SO₄, CH₃-CH₂OH, CH₃-O-CH₃, CH₃-COOH, and H-COOH. 2. Since no specific question or mathematical problem is given, it seems to be a listing of chemical formulas, possibly for naming or categorization. 3. Without additional instructions or math-related tasks, no further algebraic or arithmetic work can be performed. 4. Please provide a specific question or request related to these formulas to proceed further.