What are the empirical formulas of each of the following substances? (a) Ibuprofen, a headache remedy: 75.69% C, 15.51% O, 8.80% H

Verified step by step guidance

Convert the percentage of each element to grams, assuming you have 100 grams of the substance. This means you have 75.69 grams of C, 15.51 grams of O, and 8.80 grams of H.

Convert the mass of each element to moles by dividing by their respective molar masses: C (12.01 g/mol), O (16.00 g/mol), and H (1.01 g/mol).

Determine the mole ratio of the elements by dividing each element's mole value by the smallest number of moles calculated in the previous step.

If necessary, multiply the mole ratios by a whole number to get whole numbers for each element in the formula.

Write the empirical formula using the whole number mole ratios as subscripts for each element.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.

Video duration:

Was this helpful?

Key Concepts

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

Empirical Formula

The empirical formula of a compound represents the simplest whole-number ratio of the elements present in that compound. It is derived from the percentage composition of each element, allowing chemists to understand the basic composition without detailing the molecular structure.

Percentage Composition

Percentage composition refers to the mass percentage of each element in a compound. It is calculated by dividing the mass of each element by the total mass of the compound and multiplying by 100. This information is crucial for determining the empirical formula from the given data.

Molar Mass

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It is essential for converting between grams and moles, which is necessary when calculating the empirical formula from the percentage composition of elements in a compound.

Recommended video:

Guided course

02:11

Molar Mass Concept

Related Practice

Textbook Question

What are the empirical formulas of substances with the following mass percent compositions? (c) Sodium thiosulfate (photographic 'fixer'): 30.36% O, 29.08% Na, 40.56% S

Textbook Question

Ferrocene, a substance proposed for use as a gasoline additive, has the percent composition 5.42% H, 64.56% C, and 30.02% Fe. What is the empirical formula of ferrocene?

Textbook Question

What is the empirical formula of stannous fluoride, the first fluoride compound added to toothpaste to protect teeth against decay? Its mass percent composition is 24.25% F, 75.75% Sn.

Textbook Question

What are the empirical formulas of each of the following substances? (b) Magnetite, a naturally occurring magnetic mineral: 72.36% Fe, 27.64% O

Textbook Question

What are the empirical formulas of each of the following substances? (c) Zircon, a mineral from which cubic zirconia is made: 34.91% O, 15.32% Si, 49.77% Zr

Textbook Question

An unknown liquid is composed of 5.57% H, 28.01% Cl, and 66.42% C. The molecular weight found by mass spectrometry is 126.58. What is the molecular formula of the compound?