3.5 NOTES Mixtures and Pure Substances

III. Mixtures of Matter A. Mixtures 1. Definition two or more substances that have been combined but have not been bonded (chemically)

c. Alloys, amalgams metal – metal solution 2. Types of mixtures a. Heterogeneous non-uniform, can see the various parts, looks different; large particles examples – mud puddle, Italian dressing; supreme pizza; salad b. Homogeneous = solution uniform; appears the same throughout; particles are not visible examples – Kool-Aid; salt water; formed when one substance dissolves in another; solute – what gets dissolved; solvent – does the dissolving; unique properties c. Alloys, amalgams metal – metal solution brass (Cu + Zn) bronze (Cu + Sn) steel (Fe + C + Cr/Mn/others) amalgams – Hg based alloys; used to be found in dental work

B. Separating mixtures 1. Filtration process of separating a liquid from a solid through a filter/porous barrier. Equipment: filter paper & funnel; liquid that passes through the filter is the filtrate; solid left behind is sometimes referred to as the residue

B. Separating mixtures 2. Distillation process of separating two or more liquids based on their boiling points; liquid pulled off is the distillate;

B. Separating mixtures 3. Crystallization process of separating a solute from the solvent; solvent is evaporated; solute will crystallize as the solvent is removed; example - rock candy.

B. Separating mixtures 4. Chromatography separates the components of a mixture (mobile phase) based on the likelihood the components will travel through a medium (stationary phase)

IV. Elements and Compounds A. Elements substance composed of one type of atom; cannot be separated into smaller particles without losing its properties; 91 naturally occurring elements, remaining elements are synthetic; pure homogeneous substance;

1. Symbols two letters (1st – capital, 2nd – lower case); most are based on English name; 10 are based on the Latin name Lead – plumbum (Pb) Mercury – hydrargyrum (Hg) Sodium – natrium (Na) Potassium – kalium (K) Antimony – stibnium (Sb), Copper – cuprum (Cu) Iron – ferrum (Fe) Silver – argentum (Ag) Gold – aurum (Au) Tin – Stannium (Sn)); 1 is based on German name (Tungsten – wolfrum (W)); symbols/names are determined by IUPAC

2. Atomic mass: average mass of compound (determined by numbers of protons and neutrons) 3. Diatomic elements seven elements that bond to each for stability; will always be found together when they are in the elemental form; symbol written with a subscript 2; H2, N2, O2, F2, Cl2, Br2, I2; Professor BrINClHOF   4. Allotropes atoms of the same element found in the same state but with different structure; carbon - graphite, diamond, buckminster fullerenes; oxygen –molecular oxygen, ozone

B. Compounds 1. Definition substance composed of more than one type of atom; homogeneous substances with a definite composition by mass; when elements combine/bond together, new properties are seen; cannot be separated into smaller particles without losing its new properties, but can be separated back into atoms; written with formulas where the subscript describes how many of each type of atom is present.