The koala dines exclusively on eucalyptus leaves. Its digestive system detoxifies the eucalyptus oil, a poison to other animals. The chief constituent in eucalyptus oil is a substance called eucalyptol, which contains 77.87% C, 11.76% H, and the remainder 0.: (a) What is the empirical formula for this substance? (b) A mass spectrum of eucalyptol shows a peak at about 154 amu. What is the molecular formula of the substance?
Step-by-step solution Step 1 of 5 Answer Koala dines exclusively on eucalyptus leaves .its digestive system detoxifies the eucalyptus oil,a poison to other animals . The chief constituent in eucalyptus oil is a substance called eucalyptol Eucalyptol is a natural organic compound that is a colorless liquid. It is a cyclic ether and a monoterpenoid. Eucalyptol is also known by a variety of synonyms: 1,8-cineol, 1,8-cineole, cajeput oil, 1,8-epoxy-p-menthane, 1,8-oxido-p-menthane, eucalyptol, eucalyptol, 1,3,3-trimethyl-2-oxabicyclo[2,2,2]octane, cineol, cineole. In 1870, F. S. Cloez identified and ascribed the na ucalyptol to the dominant portion of Euc alyptus globulus oil. It contains carbon ,hydrogen,oxygen in 77.87% C, 11.76% and remainder is oxygen . Now we have to know the empirical formula of the compound eucalyptol. Step 5 of 5 In a chemical formula, the subscripts represent the ratio of number of moles of each element that combine to form one mole of the compound. If we assume exactly 100g sample of the compound we know the mass of each element in the compound. Assume that we have 100g of eucalyptol containing 77.87 grams of carbon, 11.76 grams of Hydrogen and 10.37grams of oxygen. As subscripts represent the mole ratio, we need to convert the grams of each element to moles. The conversion factor needed is the molar mass of each element. Let n represent the number of moles of each element so that Now we arrive at a formula C 6.48311.660.648ut as the chemical formulas are written in whole numbers we have to make this real numbers to whole numbers.For this convert the real numbers to whole number divide all the numbers by smallest subscript(0.648) Now the emperical formula for eucalyptol is C H O 10 18 Structure of Eucalyptol A mass spectrum is an intensity vs. m/z (m ass-to-charge ratio) plot representing a chemical analysis. Hence, the mass spectrum of a sample is a pattern representing the distribution of ions by mass (more correctly: mass-to-charge ratio) in a sample. (b) As the mass spectrum of eucalyptol shows a peak at about 154 amu. Now the weight of C H O is 10 18 10 × 12.01 + 18 × 1.008 + 1 × 16.00 120.1 + 18.144 + 16 = 154.244 Hence molecular formula wt = 154.244; Molecular formula is C H O10 18