Ch.3 - Molecules and Compounds

Tro - Chemistry: A Molecular Approach 6th Edition

Tro6th EditionChemistry: A Molecular ApproachISBN: 9780137832217Not the one you use?Change textbook

Tro 6th Edition

Ch.3 - Molecules and Compounds

Problem 98b

Chapter 3, Problem 98b

Calculate the empirical formula for each natural flavor based on its elemental mass percent composition. b. vanillin (responsible for the taste and smell of vanilla): C 63.15%, H 5.30%, O 31.55%

Name: Chemistry: A Molecular Approach
Author: Tro
ISBN: 9780137832217

Verified step by step guidance

Step 1: Assume you have 100 grams of vanillin, which makes the mass of each element equal to its percentage composition.

Step 2: Convert the mass of each element to moles by dividing by its atomic mass. For carbon (C), use 12.01 g/mol; for hydrogen (H), use 1.008 g/mol; and for oxygen (O), use 16.00 g/mol.

Step 3: Determine the mole ratio of the elements by dividing each element's mole value by the smallest number of moles calculated in Step 2.

Step 4: If necessary, multiply the mole ratios by a whole number to get whole numbers for each element.

Step 5: Write the empirical formula using the whole number mole ratios as subscripts for each element.

Key Concepts

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

Empirical Formula

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

Mass Percent Composition

Mass percent composition indicates the percentage by mass 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 elemental percentages.

Mole Concept

The mole concept is a fundamental principle in chemistry that relates the mass of a substance to the number of particles it contains. One mole of any substance contains Avogadro's number (approximately 6.022 x 10^23) of entities, allowing for conversions between mass and moles, which is essential for calculating empirical formulas from mass percent data.

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Mole Concept

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Calculate the empirical formula for each stimulant based on its elemental mass percent composition.

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A chemist decomposes samples of several compounds; the masses of their constituent elements are listed. Calculate the empirical formula for each compound. c. 2.128 g Be, 7.557 g S, 15.107 g O

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