PROTEINS

Matter and ChangeMixturesMixture: A physical blend of two or more components. Salad Chicken noodle soup

Heterogeneous vs. HomogeneousHeterogeneous MixturesA mixture in which the composition is not uniform throughout.Chicken soup ingredients are not evenly distributed.

Homogeneous MixturesA mixture in which the composition is uniform throughout. Homogeneous MixturesSolution: Another name for a homogeneous mix.Many are liquidsCan be gas (air)Can be a solid (stainless steel = iron + chromium = nickel)Phase: Term used to describe any part of a sample with uniform composition and properties.Homogeneous mix. contains one single phase.

Homogeneous MixturesOlive oil (Olives oil and different waxes)Vinegar (water and acidic acid)

=Homogeneous MixturesOlive oil Vinegar (water and acidic acid)

When mixed together they form layers. Both layers are phases.The oil phase floats on the water phase. Both are mixturesSeparating MixturesDifferences in Physical properties can be used to separate mixtures.

Separating Olive oil and Vinegar Method one: pour off the oil. (oil floats on water)Method two: freeze. Oil freezes before vinegar.Separating MixturesFiltration: separating a solid from a liquid.Distillation: boiling a liquid to produce a vapor then condensed into a liquid.

Section 2.4 Chemical Rxn.Physical Change: some properties of a material changes but the composition does not.

Chemical Change: composition of matter always changes.

Chemical property: The ability of a substance to undergo a specific chemical change.Ex. The ability to rust.Chemical Properties.Are important because they can be used to identify a substance.

Can be observed only when a substance undergoes a chemical change.

Physical vs. Chemical Physical Change: Iron and sulfide get separated with the use of a magnet.

Chemical Change: Iron and oxygen form rust.

Chemical ReactionsWhen one or more substances change into one or more new substances.A chemical change is also called a chemical Rxn.

Reactant ProductSubstance present at the beginningSubstance producedChemical ReactionsReactant ProductSubstance present at the beginningSubstance produced4 Clues to Chemical ChangesTransfer of EnergyEvery chem. Rxn involves energy.A change in color.Cooked food browns illustrating a chem. Change.The production of a gas.The bubbles from soap scum and cleaner.Formation of a precipitate.Our demo on Tuesday.Law of Conservation of MassIn any physical change of chemical reaction mass is neither created or destroyed.

During a chemical reaction the mass of the products is always equal to the mass of the reactants.