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
Nature of Energy
Kinetic & Potential Energy
First Law of Thermodynamics
Internal Energy
Endothermic & Exothermic Reactions
Heat Capacity
Constant-Pressure Calorimetry
Constant-Volume Calorimetry
Thermal Equilibrium
Thermochemical Equations
Formation Equations
Enthalpy of Formation
Hess's Law
Additional Guides

The Internal Energy of a system is the total energy from all forms of kinetic and potential energy. 

Internal Energy of a system

Concept #1: Internal Energy

Concept #2: Internal Energy Formula

The internal energy of the system: ΔE = q + w

Example #1: What is in the internal energy of the system if the reaction is done at a constant pressure of 20.0 atm and the volume compresses from 10 L to 5 L while releasing 92.2 kJ of heat?

Practice: An unknown gas expands in a container increasing the volume from 4.3 L to 8.2 L at a constant pressure of 931 mmHg. Calculate the internal energy of the system if the system absorbs 2.3 kJ of energy. 

Practice: A gas reaction is allowed to take place in a canister while submerged in water at a temperature of 25oC. The gas expands and does P-V work on the surroundings equal to 385 J. At the same time, the temperature of the water decreases to 20oC as the energy in the gas reaction reaches 364 J. What is the change in energy of the system?