Textbook Question
What is the molecular formula of each of the following compounds? (a) empirical formula CH, molar mass 5 78.0 g/mol (b) empirical formula NH2Cl, molar mass = 51.5 g/mol
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Ch.3 - Chemical Reactions and Reaction Stoichiometry
Brown15th EditionChemistry: The Central ScienceISBN: 9780137542970
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Table of contents
- Ch.1 - Introduction: Matter, Energy, and Measurement111
- Ch.2 - Atoms, Molecules, and Ions166
- Ch.3 - Chemical Reactions and Reaction Stoichiometry138
- Ch.4 - Reactions in Aqueous Solution127
- Ch.5 - Thermochemistry104
- Ch.6 - Electronic Structure of Atoms109
- Ch.7 - Periodic Properties of the Elements107
- Ch.8 - Basic Concepts of Chemical Bonding102
- Ch.9 - Molecular Geometry and Bonding Theories120
- Ch.10 - Gases122
- Ch.11 - Liquids and Intermolecular Forces79
- Ch.12 - Solids and Modern Materials102
- Ch.13 - Properties of Solutions99
- Ch.14 - Chemical Kinetics153
- Ch.15 - Chemical Equilibrium83
- Ch.16 - Acid-Base Equilibria109
- Ch.17 - Additional Aspects of Aqueous Equilibria117
- Ch.18 - Chemistry of the Environment60
- Ch.19 - Chemical Thermodynamics109
- Ch.20 - Electrochemistry113
- Ch.21 - Nuclear Chemistry79
- Ch.22 - Chemistry of the Nonmetals52
- Ch.23 - Transition Metals and Coordination Chemistry57
- Ch.24 - The Chemistry of Life: Organic and Biological Chemistry7
Brown15th EditionChemistry: The Central ScienceISBN: 9780137542970Not the one you use?Change textbook
Chapter 3, Problem 48c
Determine the empirical formulas of the compounds with the following compositions by mass: c. 62.1% C, 5.21% H, 12.1% N, and the remainder O
Verified step by step guidance1
Step 1: Assume you have 100 grams of the compound. This way, the percentages can be directly converted to grams.
Step 2: Convert the mass of each element to moles by dividing by their respective molar masses: C (12.01 g/mol), H (1.008 g/mol), N (14.01 g/mol), and O (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 ratios by a whole number to get whole numbers for each element in the formula.
Step 5: Write the empirical formula using the whole number 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 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.
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Empirical vs Molecular Formula
Mass Percent Composition
Mass percent composition refers to 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 given mass 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.
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Related Practice
Textbook Question
The compound XCl4 contains 75.0% Cl by mass. What is the element X?
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Textbook Question
Determine the empirical formula of each of the following compounds if a sample contains b. 5.28 g Sn and 3.37 g F;
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Textbook Question
Determine the empirical formulas of the compounds with the following compositions by mass: a. 55.3% K, 14.6% P, and 30.1% O
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Textbook Question
Determine the empirical formula of each of the following compounds if a sample contains c. 87.5% N and 12.5% H by mass.
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Textbook Question
A compound whose empirical formula is XF3 consists of 65% F by mass. What is the atomic mass of X?
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