Question: what is the empirical formula for monosaccharides?
Answer: With few exceptions (e.g., deoxyribose), monosaccharides have this chemical formula: (CH2O)x, where conventionally x ≥ 3. Monosaccharides can be classified by the number x of carbon atoms they contain: triose (3), tetrose (4), pentose (5), hexose (6), heptose (7), and so on.