Ch. 8.1 The Nature of Matter
Matter
• made up of atoms
• elemental molecules = element
• compounds & molecules ‐ 2 or more different elements combined in definite proportions
• pure substance = 1 type of atom, molecule or compound; cannot be separated by physical means
(ex. oxygen, water, sodium chloride)
Properties of SOME, but not all matter are:
• boiling point
• melting point
• flammability
• color of flame when burned
• solubility in water or other liquids
• color
• smell
• shape (on a molecular level, think of crystals)
• reactivity with other chemicals
• conductivity of electricity or heat
Properties of ALL matter:
• mass: amount of matter (atoms) in an object
• volume: amount of space an object takes up
• density: the mass per unit volume of an object
Homogeneous Mixture
• is the same throughout
• often can’t see different particles mixed together
• often difficult to separate
examples: air, steel, milk, salt water, Kool Aid®
Mixtures: a blend of two or more substances that are not chemically combined.
Heterogeneous Mixture
• different samples are not necessarily made up of exactly the same proportions of matter
• can often see different particles mixed together
• often can be easily separated