Skip to main content
Ch.1 - Structure and Bonding
Wade - Organic Chemistry 9th Edition
Wade9th EditionOrganic ChemistryISBN: 9780135213728Not the one you use?Change textbook
Chapter 1, Problem 47b

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.

Verified step by step guidance
1
Step 1: Begin by determining the empirical formula of compound X. Assume a 100 g sample of the compound, which means it contains 62.0 g of carbon and 10.4 g of hydrogen. The remaining mass will be oxygen, as no nitrogen or halogen is present.
Step 2: Convert the masses of carbon and hydrogen to moles. Use the molar mass of carbon (12.01 g/mol) and hydrogen (1.008 g/mol) to find the number of moles of each element.
Step 3: Calculate the moles of oxygen by subtracting the mass of carbon and hydrogen from the total mass (100 g) to find the mass of oxygen, then convert this mass to moles using the molar mass of oxygen (16.00 g/mol).
Step 4: Determine the simplest whole number ratio of moles of carbon, hydrogen, and oxygen to find the empirical formula. Divide the moles of each element by the smallest number of moles calculated in the previous steps.
Step 5: Use the empirical formula to calculate its molar mass. Compare this with the given molecular weight of compound X (117 g/mol) to find the molecular formula. Multiply the subscripts in the empirical formula by a whole number to match the molecular weight.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
8m
Was this helpful?

Key Concepts

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

Empirical Formula Calculation

The empirical formula represents the simplest whole-number ratio of elements in a compound. To find it, convert the percentage composition of each element to moles by dividing by their atomic masses. Then, divide each by the smallest number of moles to get the simplest ratio. This step is crucial for determining the molecular formula.
Recommended video:
Guided course
00:46
Calculating IHD using molecular formula

Molecular Formula Determination

The molecular formula is a multiple of the empirical formula and represents the actual number of atoms of each element in a molecule. To find it, calculate the empirical formula mass and divide the given molecular weight by this mass. The result is the factor by which the subscripts in the empirical formula must be multiplied to obtain the molecular formula.
Recommended video:
Guided course
02:17
How to use IHD with molecular formula.

Elemental Analysis

Elemental analysis involves determining the percentage composition of each element in a compound. This data is essential for calculating the empirical formula. In this problem, the analysis shows the presence of carbon and hydrogen, which guides the calculation of the empirical formula and subsequently the molecular formula, given the absence of nitrogen and halogens.
Recommended video:
Guided course
06:56
Understanding the Element Effect.
Related Practice
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.

b. The molecular weight of estradiol was later determined to be 272. Determine the molecular formula of estradiol.

1494
views
1
rank
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

788
views
Textbook Question

Use resonance structures to identify the areas of high and low electron density in the following compounds:

g.

h.

669
views
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
views
Textbook Question

Use resonance structures to identify the areas of high and low electron density in the following compounds:

i.

j.

482
views
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

1084
views