C13H19O2 = (12 * 13) + (1 *19) + (16 *2) = 156 + 19 + 32 = 207. The formula is n = molar mass of molecular formular / molar mass of empirical formular. MM of molecular formula = 414.7 and of empirical formula =207 So n = 414.7 / 207 = 2. So the true molecular formula is 2(C13H19O9) = C26H38O18.
