2Matter Matter is classified as substances and mixtures. Matter has mass and takes up spaceMixture – composition variable, can be separated by a physical meansElement – composition definiteCompound – two or more elements combined
3Pure Substances Element matter composed of identical atoms All atoms are the sameEX: copper
4Classifying MatterColloid vs. Solution-pass a beam of light through the mixtureIf the beam is invisible- it is a solutionIf the beam is visible- it is a colloidThe visible beam through the colloid is called the Tyndall effectSuspension- heterogeneous mixture containing a liquid in which visible particles settle out over time – like dirty water and Italian salad dressing
5Mixtures Variable combination of 2 or more pure substances. Homogeneous Mixture (AKA -Solution)even distribution of componentsvery small particlesparticles never settleEX: saline solution, fresh pickle juice
6Mixtures Heterogeneous Mixture uneven distribution of components colloids and suspensionsEX: granite
7Pure Substances Compound matter composed of 2 or more elements in a fixed ratioproperties differ from those of individual elementsNOT a mixtureEX: salt (NaCl)
8Mixtures Colloid medium-sized particles Tyndall effect - particles scatter light (looks cloudy)particles never settleEX: milk, fog
9Tyndall Effect Because of the Tyndall effect, A light beam is Scattered by the Colloid suspensionOn the right, but Passes invisiblyThrough the solutionOn the left.
10Physical PropertiesPhysical Property- any characteristic of a material that you can observe or attempt to observe without changing the identity of the substanceFor example: color, shape, size, melting point, and boiling point, how it flows.Metallic aluminum: Silvery color, easily formed, reflects heat.Behavior of substances- magnetism, ductility- ability of metal to be drawn into wires; malleability- ability of metal to be shaped- pounded into sheets; ability to flow
11Physical ChangeA change in the form of a substance without changing its identity.properties remain the samereversiblecan be used to separate mixturesEX: dissolving, grinding, distillation, mixing sugar and salt
12Physical ChangesDistillation- separating a solution of two liquids through evaporatinga liquid andre-condensingits vapor.Vapors from the liquidwith the lowest boilingpoint form first and arecondensed andcollected
13Chemical PropertyA characteristic that indicates whether a substance can undergo a specific chemical change.EX: flammability, reactivity, resistance of a diamond to corrosionChemical changes can be used to separate substances- done in labs- metals can be removed from ore this way
14Chemical and Physical Weathering Physical weathering when rocks split as water freezes or as erosion occursChemical weathering when acidic water reacts with limestone and results in a new substance that dissolves in water and washes away.
15Law of Conservation of Mass Mass cannot be created or destroyedBurning a log seems to make mass disappear“missing” mass is actually present in the gases that are produced as the log burnsWhen the log burns new substances are formed.EX: Iron and oxygen combining to form rust, the masses will still be equal.