Classification of Matter

Matter is anything that has mass and takes up volume We call that DENSITY Density = mass/volume

How can matter be classified? Matter can be divided into two categories Pure Substances – cannot be physically separated Mixtures – can be physically separated

Pure Substances can be divided into two categories Elements – cannot be chemically separated (made up of one kind of atom) Compounds – can be chemically separated (made up of two or more elements)

Examples Elements – C, H, O, N, P, S Compounds – NaCl, H2O, CO2, C6H1206

Compounds form to allow elements to become more stable Example: Na is flammable around H2O, and Cl is a toxic gas. When they form a compound together, it is neither flammable nor toxic Compounds form depending on the number valence electrons of 2 or more elements – need 8 valence electrons to be stable Example: Na has 1 valence electron and Cl has 7 valence electrons. They form a compound together called salt.

Mixtures can be divided into two categories Homogeneous Mixtures – all the parts are evenly distributed (not visible) Consists of ONE phase! Heterogeneous Mixtures – all the parts are unevenly distributed (visible) Consists of more than 1 phase!

Examples Homogeneous Mixtures – tea, water, coke Heterogeneous Mixtures – pizza, trail mix

Homogeneous Mixtures are commonly known as solutions Parts of a Solution Solution = Solute + Solvent Solute - “stuff” being dissolved Solvent - “stuff” doing the dissolving Example: Salt water Salt = solute Water = solvent

Types of Solution Hypotonic – concentration of solvent is greater than concentration of solute Hypertonic – [ ] of solute is greater than [ ] of solvent Isotonic – [ ] of both solvent and solute is equal

Methods in Separating Mixtures Filtration – separates an insoluble solid from a liquid Evaporation – separates a soluble solid from a liquid Magnetism – separates solid substances, one of which is magnetic Floating – separates substances based on their density – more dense on the bottom, less dense on the top By Hand – separates substance by hand picking them out

Filtration

Evaporation

Magnet

Floating

By Hand

Pure Substance or Mixture? Helium Kool-Aid Milk Salt Copper Ketchup Pure Substance (Element) Mixture Mixture Pure Substance (Compound) Pure Substance (Element) Mixture

B C A E D A, B C, E D