Chemistry

The branch of science that deals with the identification of the substances of which matter is composed; the investigation of their properties and the ways in which they interact, combine, and change; and the use of these processes to form new substances.

• term

  acid

  definition

  a compound which, when dissolved in water, gives a pH of less than 7.0, or donates a hydrogen ion.

• term

  base

  definition

  a substance that accepts a proton and has a pH above 7.0. A common example is sodium hydroxide (NaOH)

• term

  atom

  definition

  a chemical element in its smallest form, made up of protons and neutrons within the nucleus and electrons circling the nucleus.

• term

  atomic mass

  definition

  the mass of an atom, typically expressed in unified atomic mass units and nearly equivalent to the mass number.