Elements Atoms make up elements Elements are the

Elements • Atoms make up elements • Elements are the simplest pure substances (ex. Hydrogen, Helium, Oxygen); can’t be broken down by chemical means – 92 naturally occurring; Earth’s crust is mostly Oxygen and Silicon

Compounds • Compounds are pure substances that are formed when 2 or more elements combine • Ex. Water – made up of 2 atoms of Hydrogen and 1 atom of Oxygen; all water molecules have the same properties

What’s a Mixture? ? • Combo of two or more substances; are physically but not chemically combined • May be separated by physical meansevaporation, filtration, magnets, picking out pieces, etc. • Exist in any phase- liquids (ethanol & gas); liquid/gas (Coke®); solids (taco salad); gas/solid (smoke)

Heterogeneous mixture -not the same throughout; “least mixed” -larger particles -easier to separate -examples: salad dressing, your sock drawer, cereal, sand, rocks, soil

Homogeneous Mixture • “well mixed” • Examples include: glass, iced tea, stainless steel, smoke, toothpaste

A Type of Homogeneous Mixture… • Solutions- “best mixed; ” made of a substance that is dissolved (solute) and a substance that does the dissolving (solvent) – In other words: the solvent dissolves the solute Examples: lemonade, coffee, soda, ocean water, dental filling

Did You Know…. …. that not all solutions are liquids? • Alloys- metal solutions that are solids dissolved in solids (ex. Gold jewelry is gold and copper dissolved together)