Textbook Question
Imagine that you are climbing a mountain. Which of the following are state functions? b. The change in elevation during the climb
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Ch.5 - Thermochemistry
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 5, Problem 32
How much work (in J) is involved in a chemical reaction if the volume decreases from 5.00 to 1.26 L against a constant pressure of 0.857 atm?
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Identify the formula for work done in a chemical reaction involving gases: \( w = -P \Delta V \), where \( w \) is the work done, \( P \) is the pressure, and \( \Delta V \) is the change in volume.
Calculate the change in volume \( \Delta V \) by subtracting the final volume from the initial volume: \( \Delta V = V_{\text{final}} - V_{\text{initial}} = 1.26 \text{ L} - 5.00 \text{ L} \).
Convert the pressure from atm to the SI unit of pressure, pascals (Pa), using the conversion factor: \( 1 \text{ atm} = 101325 \text{ Pa} \).
Convert the volume change from liters to cubic meters (m³) using the conversion factor: \( 1 \text{ L} = 0.001 \text{ m}^3 \).
Substitute the values of pressure in pascals and volume change in cubic meters into the work formula to calculate the work done in joules.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Work in Thermodynamics
In thermodynamics, work is defined as the energy transferred when a force is applied over a distance. For chemical reactions occurring at constant pressure, the work done by or on the system can be calculated using the formula W = -PΔV, where P is the pressure and ΔV is the change in volume. A negative sign indicates that work is done by the system when it expands.
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First Law of Thermodynamics
Pressure-Volume Work
Pressure-volume work is a specific type of work associated with the expansion or compression of gases. It occurs when a gas changes its volume against an external pressure. The work done is directly proportional to the pressure and the change in volume, making it essential to understand how these variables interact in a chemical reaction.
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Units of Work
In chemistry, work is typically measured in joules (J). To convert pressure from atmospheres to pascals (1 atm = 101.325 kPa) and volume from liters to cubic meters (1 L = 0.001 m³), it is crucial to ensure that all units are consistent when calculating work. This ensures accurate results in thermodynamic calculations.
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Related Practice
Textbook Question
Imagine that you are climbing a mountain. Which of the following are state functions? a. The distance you walk during your climb to the top
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Textbook Question
Consider a system consisting of two oppositely charged spheres hanging by strings and separated by a distance r1, as shown in the accompanying illustration. Suppose they are separated to a larger distance r2, by moving them apart. (a) What change, if any, has occurred in the potential energy of the system?
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Textbook Question
A gas is confined to a cylinder under constant atmospheric pressure, as illustrated in Figure 5.4. When 0.49 kJ of heat is added to the gas, it expands and does 214 J of work on the surroundings. What are the values of H and E for this process?
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