Topic: Matter & Energy Aim: What is matter? Do Now: What is an element? HW:

Chemistry… Studies matter –Takes up space, has mass 2 types of substances –pure –definite composition

Substances

Element can’t be broken down –only made of themselves), on Periodic Table –Basic unit - atom

Particle Diagrams – Elements Arrangement can vary – monatomic, diatomic, polyatomic – but only ONE TYPE of atom is present

Compound 2 or more DIFFERENT elements chemically combined –Properties different than properties of elements that make them up –Ex: formation of water: 2H 2 + O 2  2H 2 O –Basic unit molecule (covalent – only nonmetals) formula unit (ionic – metal & nonmetal) Can only be broken down by chemical means

Compounds

Particle Diagrams – Compounds Again, arrangement can vary, but CONSTANT RATIO is present

Mixtures >1 substance physically combined –Components retain their properties –Can be separated by physical means Heterogeneous mixture –Not uniform, components easily distinguished –Salt & pepper, soil, sand & water Homogeneous mixture –Uniform, components not easily distinguished –Solutions (salt & water), alloys (gold, bronze)

Heterogeneous Mixture

Homogeneous Mixture

Particle Diagrams - Mixtures

Divisions of Matter

Practice Question – Which represents a mixture?

Which sample represents a pure substance? Why is a sample like xx NOT a compound?

Substance or Mixture? Why? Chlorine Water Soil Sugar water Oxygen Carbon dioxide Rocky road ice cream Iron

Methods of Separating Mixtures Since mixtures are only physical combinations of substances, they can be separated by physical means. Chemical bonds aren’t breaking Attractions between neighboring particles are breaking

Distillation - separates mixtures based on different boiling points

Filtration - separates a liquid from a solid - liquid passes through filter paper, solid particles get trapped in the filter paper

Chromatography- separates molecules in a mixture based on size

Centrifuge- spins, separates mixtures by density

Magnetism