Definition
Chemistry is the study of matter — its composition, structure, properties and the changes it undergoes.
Two main branches: Organic chemistry (carbon-based compounds, e.g. digestion of food, plastics) and Inorganic chemistry (everything else, e.g. metal refining, minerals).
Definition
Plasma: an ionized gas (electrons stripped from atoms), found in fluorescent tubes and lightning — the state matter takes at very high energy.
Supercritical fluid: exists above a substance's critical temperature and pressure, with properties between a liquid and a gas — useful as an industrial solvent because it flows like a gas but dissolves like a liquid.
Definition
Homogeneous mixture: uniform composition throughout, particles too small to see (a true solution, e.g. salt water).
Heterogeneous mixture: composition varies from point to point, particles may be visible.
Colloid: particles larger than a true solution's but too small to settle out, scattered through a medium (e.g. milk).
Definition
Solubility is the maximum amount of a solute that dissolves in a given amount of solvent at a given temperature. For most solids, solubility increases with temperature; for gases, it decreases as temperature rises.
Rule
Crystalline solids have a regular, repeating particle arrangement (a definite geometric shape, e.g. diamond); amorphous solids have no such long-range order (e.g. glass, plastic).
Remember
Diamond's brilliance comes from its rigid, symmetric crystal structure, which bends and reflects light in a very specific, sparkling way — cutting a diamond precisely enhances this by controlling how light enters and exits.
Definition
Allotropes are different structural forms of the same element — e.g. carbon as diamond (hard, insulator) and graphite (soft, conducts electricity), because their atoms are arranged differently.
Graphene (a single layer of carbon atoms) is exceptionally strong, light and electrically conductive — called a "miracle material" for its potential in electronics and materials science.
Quick Recap
- ●Chemistry: organic (carbon compounds) and inorganic (everything else)
- ●Plasma: ionized gas. Supercritical fluid: between liquid and gas, above critical point
- ●Homogeneous: uniform. Heterogeneous: varies. Colloid: in between, doesn't settle
- ●Solubility: most solids up with temperature; gases down with temperature
- ●Crystalline: regular repeating structure. Amorphous: no long-range order
- ●Allotropes: same element, different structure (diamond vs graphite); graphene = one-atom-thick carbon sheet
