Energy and Chemical Reactions
Unit 2: Chapters 6 and 7
Exams will cover chapters six and seven.
Lab Attendance Policy: Missing more than two labs technically results in a class failure according to the syllabus; however, students are advised to speak with the instructor to explore options to avoid this consequence.
Forms and Types of Energy
Kinetic Energy: Energy of motion.
Potential Energy: Stored energy. For example, food contains potential energy, which converts to usable energy upon consumption.
Chemical Energy: The energy stored in the bonds between molecules.
When two molecules form a bond, they possess chemical energy.
Chemicals simply existing and bonding to each other create chemical energy.
Mechanical Energy: The energy of motion, such as walking. This broadly relates to thermodynamics.
Laws of Thermodynamics
First Law of Thermodynamics (Law of Conservation of Energy):
Energy cannot be created or destroyed.
Energy can only be changed from one form to another.
Examples: Potential energy can be converted to kinetic energy, kinetic to potential, chemical to mechanical, and so on.
This conversion occurs without a loss of usable energy in the absolute sense (total energy remains constant).
Second Law of Thermodynamics (Law of Entropy):
Energy conversions are not 100\% efficient.
During every energy conversion, some energy is lost, typically in the form of heat (dissipation of heat).
Example: Plants convert solar energy into chemical energy, but some energy is dissipated as heat during this process.
Example: When humans eat plants, the stored chemical energy is converted into mechanical energy (e.g., walking), again dissipating heat during the conversion. This released heat cycles back into the atmosphere.
Heat lost to the environment cannot be readily recaptured and converted back into another type of usable energy; it's considered