Textbook Question
(a) Calculate the mass percentage of Na2SO4 in a solution containing 10.6 g of Na2SO4 in 483 g of water.
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Ch.13 - Properties of Solutions
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 13, Problem 42a
A solution is made containing 20.8 g of phenol (C6H5OH) in 425 g of ethanol (CH3CH2OH). Calculate (a) the mole fraction of phenol,
Verified step by step guidance1
First, calculate the number of moles of phenol (C6H5OH). Use the formula: \( \text{moles} = \frac{\text{mass}}{\text{molar mass}} \). The molar mass of phenol is approximately 94.11 g/mol.
Next, calculate the number of moles of ethanol (CH3CH2OH). Use the same formula: \( \text{moles} = \frac{\text{mass}}{\text{molar mass}} \). The molar mass of ethanol is approximately 46.07 g/mol.
Add the moles of phenol and the moles of ethanol to find the total number of moles in the solution.
Calculate the mole fraction of phenol using the formula: \( \text{mole fraction of phenol} = \frac{\text{moles of phenol}}{\text{total moles in solution}} \).
Ensure that the mole fraction is a dimensionless number, typically expressed as a decimal.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Mole Fraction
Mole fraction is a way of expressing the concentration of a component in a mixture. It is calculated by dividing the number of moles of the component by the total number of moles of all components in the solution. This dimensionless quantity provides insight into the relative amounts of substances in a mixture, which is particularly useful in solutions.
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Mole Fraction Formula
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 atoms in a molecule. Knowing the molar mass is essential for converting between grams and moles, which is necessary for calculating mole fractions in a solution.
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Solution Composition
Solution composition refers to the relative amounts of solute and solvent in a solution. In this case, phenol is the solute and ethanol is the solvent. Understanding the composition is crucial for calculations involving concentrations, such as mole fraction, as it helps determine how much of each component is present in the solution.