Thermodynamics: First Law and Internal Energy Concepts

These flashcards cover key vocabulary and concepts related to the First Law of Thermodynamics and internal energy.

First Law of Thermodynamics

Also known as the Law of conservation of energy; states that energy is neither created nor destroyed, and the total energy of the universe is constant.

Internal Energy (E or U)

The sum of all kinetic and potential energy within a system. E is a state function based on parameters like temperature, pressure, concentration, and phase.

State Function

A value or variable that depends only on the state of the system, not on how the state was achieved.

Change in Internal Energy (ΔE)

The difference in internal energy between the final and initial states of a system.

Heat (q)

A form of energy transfer that can cause a change in the internal energy of a system.

Work (w)

A form of energy transfer that is done by or on a system, contributing to the change in internal energy.

Energy Conservation in a System

The principle stating that the energy lost by a system is equal to the energy gained by the surroundings, and vice versa.

Sign Conventions for Heat and Work

For heat, +q means the system gains thermal energy, while -q means it loses thermal energy; for work, +w means work is done on the system, while -w means work is done by the system.

ΔE = q + w

The formula for calculating the change in internal energy, where q is the heat added to the system and w is the work done on the system.

Constant Energy of the Universe

Refers to the concept that in all processes, the change in energy of the universe is zero.