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 a balloon filled with helium at the following conditions.313 g He 1.00 atm 1910. L Molar Heat Capacity = 20.8 J/°C • molThe temperature of this balloon is decreased by 41.6°C as the volume de

Solution: Consider a balloon filled with helium at the following conditions.313 g He 1.00 atm 1910. L Molar Heat Capacity = 20.8 J/°C • molThe temperature of this balloon is decreased by 41.6°C as the volume de

Problem

Consider a balloon filled with helium at the following conditions.

313 g He 

1.00 atm 

1910. L 

Molar Heat Capacity = 20.8 J/°C • mol

The temperature of this balloon is decreased by 41.6°C as the volume decreases to 1643 L, with the pressure remaining constant. Determine q, w, and ΔE (in kJ) for the compression of the balloon.

Solution

Recall: The change in internal energy (ΔE or ΔU) is given by:

The formula for work at constant pressure is:

where ΔV = change in volume (final V – initial V).

The formula for heat at constant pressure is:

where n = moles of compound, Cp = molar heat capacity at constant pressure, and ΔT = change in temperature (final T – initial T).

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