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Ch.1 - Structure and Bonding
Wade - Organic Chemistry 9th Edition
Wade9th EditionOrganic ChemistryISBN: 9780135213728Not the one you use?Change textbook
All textbooksWade 9th EditionCh.1 - Structure and BondingProblem 48b
Chapter 1, Problem 48b

In 1934, Edward A. Doisy of Washington University extracted 3000 lb of hog ovaries to isolate a few milligrams of pure estradiol, a potent female hormone. Doisy burned 5.00 mg of this precious sample in oxygen and found that 14.54 mg of CO2 and 3.97 mg of H2O were generated.
b. The molecular weight of estradiol was later determined to be 272. Determine the molecular formula of estradiol.

Verified step by step guidance
1
Calculate the moles of carbon in the sample by using the mass of CO2 produced. Use the molar mass of CO2 (44.01 g/mol) to find the moles of CO2, and then use the ratio of carbon in CO2 to find the moles of carbon.
Calculate the moles of hydrogen in the sample by using the mass of H2O produced. Use the molar mass of H2O (18.02 g/mol) to find the moles of H2O, and then use the ratio of hydrogen in H2O to find the moles of hydrogen.
Determine the mass of carbon and hydrogen in the sample using their respective moles and atomic masses (C: 12.01 g/mol, H: 1.008 g/mol).
Subtract the mass of carbon and hydrogen from the total mass of the sample to find the mass of oxygen in the sample. Use this mass to calculate the moles of oxygen.
Determine the empirical formula by finding the simplest whole number ratio of moles of carbon, hydrogen, and oxygen. Then, use the given molecular weight of estradiol (272 g/mol) to find the molecular formula by comparing the empirical formula mass to the molecular weight.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Combustion Analysis

Combustion analysis is a method used to determine the elemental composition of a compound by burning it in oxygen and analyzing the resulting products, typically CO2 and H2O. By measuring the masses of these products, one can calculate the amounts of carbon and hydrogen in the original compound, which is essential for determining its empirical formula.
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Empirical and Molecular Formulas

The empirical formula of a compound represents the simplest whole-number ratio of the elements within it, while the molecular formula shows the actual number of each type of atom in a molecule. To find the molecular formula, one must first determine the empirical formula and then use the compound's molecular weight to scale up to the actual number of atoms.
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Molar Mass and Stoichiometry

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole. It is crucial for converting between mass and moles in stoichiometric calculations. In this context, knowing the molar mass of estradiol allows us to relate the empirical formula to the molecular formula by comparing the empirical formula mass to the given molecular weight.
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Related Practice
Textbook Question

Compound X, isolated from lanolin (sheep's wool fat), has the pungent aroma of dirty sweatsocks. A careful analysis showed that compound X contains 62.0% carbon and 10.4% hydrogen. No nitrogen or halogen was found.

b. A molecular weight determination showed that compound X has a molecular weight of approximately 117. Find the molecular formula of compound X.

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Textbook Question

Cyclopropane (C3H6, a three-membered ring) is more reactive than most other cycloalkanes.

c. Suggest why cyclopropane is so reactive.

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Textbook Question

Compound X, isolated from lanolin (sheep’s wool fat), has the pungent aroma of dirty sweatsocks. A careful analysis showed that compound X contains 62.0% carbon and 10.4% hydrogen. No nitrogen or halogen was found.

a. Compute an empirical formula for compound X

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Textbook Question

Cyclopropane (C3H6, a three-membered ring) is more reactive than most other cycloalkanes.

a. Draw a Lewis structure for cyclopropane.

b. Compare the bond angles of the carbon atoms in cyclopropane with those in an acyclic (noncyclic) alkane.

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Textbook Question

In 1934, Edward A. Doisy of Washington University extracted 3000 lb of hog ovaries to isolate a few milligrams of pure estradiol, a potent female hormone. Doisy burned 5.00 mg of this precious sample in oxygen and found that 14.54 mg of CO2 and 3.97 mg of H2O were generated.

a. Determine the empirical formula of estradiol.

801
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Textbook Question

If the carbon atom in CH2Cl2 were flat, there would be two stereoisomers. The carbon atom in CH2Cl2 is actually tetrahedral. Make a model of this compound, and determine whether there are any stereoisomers of CH2Cl2. 

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