Textbook Question
Determine the number of moles (of molecules or formula units) in each sample. a. 55.98 g CF2Cl2
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Ch.3 - Molecules, Compounds & Chemical Equations
Tro4th EditionChemistry: A Molecular ApproachISBN: 9780134112831
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Table of contents
- Ch.1 - Matter, Measurement & Problem Solving136
- Ch.2 - Atoms & Elements112
- Ch.3 - Molecules, Compounds & Chemical Equations159
- Ch.4 - Chemical Quantities & Aqueous Reactions140
- Ch.5 - Gases118
- Ch.6 - Thermochemistry106
- Ch.7 - Quantum-Mechanical Model of the Atom62
- Ch.8 - Periodic Properties of the Elements103
- Ch.9 - Chemical Bonding I: The Lewis Model104
- Ch.10 - Chemical Bonding II: Molecular Shapes & Valence Bond Theory89
- Ch.11 - Liquids, Solids & Intermolecular Forces73
- Ch.12 - Solids and Modern Material59
- Ch.13 - Solutions110
- Ch.14 - Chemical Kinetics140
- Ch.15 - Chemical Equilibrium78
- Ch.16 - Acids and Bases155
- Ch.17 - Aqueous Ionic Equilibrium176
- Ch.18 - Free Energy and Thermodynamics108
- Ch.19 - Electrochemistry118
- Ch.20 - Radioactivity and Nuclear Chemistry82
- Ch.21 - Organic Chemistry150
Chapter 3, Problem 63
Determine the number of moles (of molecules or formula units) in each sample. a. 25.5 g NO2 b. 1.25 kg CO2 c. 38.2 g KNO3 d. 155.2 kg Na2SO4
Verified step by step guidance1
insert step 1: Identify the molar mass of each compound using the periodic table. For example, calculate the molar mass of NO_2 by adding the atomic masses of nitrogen (N) and oxygen (O).
insert step 2: Convert the mass of each sample to grams if necessary. For instance, convert 1.25 kg of CO_2 to grams by multiplying by 1000.
insert step 3: Use the formula: number of moles = mass of sample (g) / molar mass (g/mol) to calculate the moles for each compound.
insert step 4: Apply the formula to each sample: a. 25.5 g NO_2, b. 1.25 kg CO_2, c. 38.2 g KNO_3, d. 155.2 kg Na_2SO_4.
insert step 5: Ensure all calculations are consistent with significant figures based on the given data.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Molar Mass
Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It is calculated by summing the atomic masses of all the atoms in a molecule or formula unit. For example, the molar mass of NO2 is approximately 46.01 g/mol, which is essential for converting grams to moles.
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Molar Mass Concept
Conversion between Mass and Moles
To determine the number of moles from a given mass, the formula used is: moles = mass (g) / molar mass (g/mol). This relationship allows chemists to convert between the mass of a substance and the amount in moles, facilitating stoichiometric calculations in chemical reactions.
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02:28Mass and Moles Conversion
Unit Conversion
Unit conversion is the process of converting a quantity expressed in one unit to another unit. In this question, it is necessary to convert kilograms to grams for CO2 and Na2SO4, as the molar mass is typically given in grams per mole. Understanding how to perform these conversions is crucial for accurate calculations.
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Related Practice
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Determine the number of moles (of molecules or formula units) in each sample. c. 0.1187 g C8H18
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Calculate the formula mass for each compound. a. MgBr2 b. HNO2 c. CBr4 d. Ca(NO3)2
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Determine the number of moles (of molecules or formula units) in each sample. b. 23.6 kg Fe(NO3)2
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