AP chem - stuff

distillation

Purifies and separates liquids with different boiling points or separates liquid from dissolved solids by heating, vaporizing, and condensing back to liquid

 chemical and physical changes 

chemical changes result in new substances

physical changes alter the form without changing the identity.

filtration

Separation of an insoluble substance from a liquid or a solution (using mesh)

chromatography

A technique used to separate components of a mixture based on their different affinities for a stationary phase and a mobile phase.

Pure substance

A material with a uniform and definite composition, which can be an element or a compound. Pure substances have consistent properties throughout, unlike mixtures.

Element

A substance that cannot be broken down into simpler substances by chemical means. Elements are the building blocks of matter, consisting of only one type of atom.

Compound

A substance formed when two or more elements are chemically bonded together in a fixed ratio. Compounds have distinct properties different from the individual elements that compose them.

Electron Affinity

The energy change associated with the addition of an electron to a gaseous atom.

Shielding

When inner core electrons push back against outer electrons (valence electrons)

Nuclear Charge

total positive charge inside an atom’s nucleus (number of protons)

Ionic radius

The distance from the center of the ion’s nucleus to the outer edge of the electron cloud. It increases down a group and decreases across a period.