Ch.6 - Thermochemistry WorksheetSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

Solution: Consider the systems shown in the following figure. In one case the battery becomes completely discharged by running the current through a heater, and in the other by running a fan. Both processes occ

Problem
Consider the systems shown in the following figure. In one case the battery becomes completely discharged by running the current through a heater, and in the other by running a fan. Both processes occur at constant pressure. In both cases the change in state of the system is the same: The battery goes from being fully charged to being fully discharged. Yet in one case the heat evolved is large, and in the other it is small.

a) Energy lost only as heat.  A diagram shows a battery connected to a resistor.  Initially, the battery is fully charged, but as energy is lost via heat, the battery is discharged.  The total energy lost by the battery is delta-E. b) Energy lost as both heat and work. A diagram shows a battery connected to a fan.  Initially, the battery is fully charged, but as energy is lost via heat and work, the battery is discharged.  The total energy lost by the battery, through both heat and work, is delta-E.

Is the enthalpy change the same in the two cases?