Mixtures versus pure substances, separation techniques, and the names, formulae and physical properties that classify everyday materials.
4 free units in this chapter
All matter is either a pure substance or a mixture, and the difference decides how you separate it.
About 3 minChemistry has a precise naming system so that a formula tells you exactly what a substance contains.
About 3 minA physical change alters form; a chemical change makes new substances. Telling them apart is a core skill.
About 3 minA balanced equation is the sentence of chemistry: it must obey conservation of mass.
About 3 min