Matter and States of Matter - Study Notes

Chemistry is a branch of science that deals with the properties, composition, and structure of elements and compounds, how they can change, and the energy released or absorbed when they change.

Matter is the subject of study in chemistry; it is anything that has mass and takes up space.
Matter exists in four fundamental states or phases: Solid, Liquid, Gas, and Plasma.

Non-matter is not a type of matter; it is a form of energy. Examples include:
- Light from a torch
- Heat from a fire
- Sound from a police siren
You cannot hold, taste, or smell these forms of energy.

Aristotle’s view: any object can be divided infinitely into smaller pieces.
In the 1800s, the belief was that if an object is cut into smaller and further smaller pieces, one may finally attain the smallest indivisible particle—atomos (Greek for “indestructible”).

Atoms: the basic particle of chemical elements; elements are distinguished by the number of protons in their atoms (atomic number, Z).
Atomic number: the number of protons in the nucleus of an atom.
Atom structure: atoms consist of a nucleus (protons and neutrons) and electrons surrounding the nucleus.
Elements: distinguished by proton count (atomic number Z).
Compound: a substance made of two or more different kinds of elements.
Molecule: a particle consisting of two or more atoms joined together in a specific arrangement.

A slide title indicates a topic: Matter And Measurement (relationship between the amount of matter and how we measure it).

States: Solid, Liquid, Gas, Plasma.
Process: Add Heat can drive phase changes (e.g., solid → liquid → gas → plasma under extreme conditions).

Particles (ions, atoms, or molecules) are closely packed.
Particles in a solid cannot move around freely; they vibrate in fixed positions.
Solids are incompressible.
Solids have a stable, definite shape and definite volume.
Solids can only change shape by applying force (e.g., breaking or cutting).

Particles are closer than in gases but can move around one another.
Liquids flow and take the shape of their container while maintaining a definite volume.
Liquids have definite volume but no fixed shape.
Particles in liquids collide as they flow, owing to attractive forces among them.
These attractions enable liquids to have a definite volume.

Gas particles can move freely and can fill the entire volume and shape of their container.
They move in random directions very quickly.
Gas particles collide with each other and with container walls, following straight-line paths between collisions.
Gas has no fixed shape or volume; it spreads to fill available space.
Intermolecular attractions in gases are negligible because particles are far apart.

Plasma is like a gas but consists of ionized atoms and free electrons; no fixed shape or volume and is less dense than solids or liquids.
It is electrically conductive, responds to magnetic fields, and emits light and radiation.
Applications include:
- Fusion energy
- Plasma TVs
- Neon signs
- Lasers
- Plasma cutting
Creation of plasma requires: heating a gas to very high temperatures or exposing it to strong electromagnetic fields, which break bonds between electrons and nuclei.

Other 4 states of matter mentioned:
- Plasma (re-listed as a state)
- Bose-Einstein Condensate
- Fermionic Condensate
- Quark-Gluon Plasma

Matter, regardless of state, is in constant random motion, possessing kinetic energy (energy of motion) that depends on temperature.
As temperature increases, atoms and molecules gain more energy and move faster.
These ideas will be examined in later topics.

Kinetic energy of a moving particle: $KE = \frac{1}{2} m v^2$
Average translational kinetic energy for particles in a gas (relation to temperature): $\langle KE \rangle = \frac{3}{2} k_B T$
Boltzmann constant and temperature link microscopic motion to macroscopic temperature: $k<em>B T$ where $kB$ is the Boltzmann constant and $T$ is the absolute temperature.
Atomic number (Z): number of protons in the nucleus; determines the identity of the element.
Subscripts and notation used in molecules (examples above) follow standard chemical formulas, e.g., Water as $H2O$, Carbon dioxide as $CO2$.

Historical context connects ancient philosophy (Aristotle) to modern atomic theory (atoms and molecules).
Distinctions among states of matter explain everyday phenomena (rigidity of solids, flow of liquids, expansion/dispersion of gases).
Plasma and exotic condensates illustrate how energy input and quantum effects create new states with unique properties and applications.
The kinetic-energy–temperature link provides foundational understanding for phase changes, diffusion, and reaction rates in real-world systems.