University of Texas
One of the 3 basics forms of matter, gases are an important part of chemistry. The behavior of gas molecules also allows us to easily model their behavior and describe it mathematically.
The atom is the basic building block of chemistry. Understanding the structure and energetics of the atom is a key to understanding more complicated particles such as molecules.
The forces between molecules will govern the physical properties of those species. These forces are categorized and ranked. IMFs are a key component to understanding chemical interactions.
All of our observable science is governed by thermodynamics - which is a study of the energy requirements and demands of matter interaction. The defined state functions and their interplay is a key part of not on chemistry, but all things in the universe.