Chapter 1 Chemical Foundations

` If data/observations do not support your hypothesis, you must start over

SI Base Units Quantity Unit Symbol Length meter m Mass kilogram kg Time second s Electric current ampere A Temperature Kelvin K Amount of substance mole mol Luminous intensity candela cd

How do we get from one unit to another unit? Dimensional Analysis- converting from one unit to another Use a conversion factor Ratio 1m = 100cm= 1000mm Do a couple of examples from the practice worksheet. Have students work selected examples for homework. Check answers the next day by putting them on the overhead transparency.

Using Scientific Measurements Significant Figures- those digits known with certainty plus one estimated digit Rules for Determining Sig. Figs. a. All nonzero digits are significant b. Zeros between nonzero digits are sig. c. Zeros appearing in front of all nonzero digits are not significant d. Zeros at the end of a number and to the right of a decimal point are significant e. Zeros at the end of a number may or may not be significant. Depends if there is a decimal. Percent error was defined in the lab. Examples: 145= 3 sig fig. 1024= 3 sf 40.7= 3 sf 87009= 5 sf .0056= 2 sf .00009= 1 sf .00306= 3 sf 85.00= 4 sf 9.000000000= 10 sf 2000 = 1 sf 2000. = 4 sf

Cont. Rounding Rules greater than 5, increase by 1 less than 5, stay the same 5 followed by nonzero digit(s), increase by 1 5, not followed by nonzero digit(s), and preceded by an odd digit, increase by 1 5, not followed by nonzero digit(s), and the preceding s.f. is even, stay the same Examples:rounder to 3 S.F. 42.68  42.7 17.32 17.3 2.7851  27.9 4.635  4.64 78.65  78.6

Cont. Addition or subtraction the answer must have the same # of digits to the right of the decimal point as there are in the measurement having the fewest digits to the right of the decimal point Multiplication and division the answer will have the same number of significant figures as the measurement with the fewest number of sig. figs. Add/sub example 2.89  2 digits + 0.00043  5 digits 2.89043  2.89 Mult./division example 3.5293  5 SF x 34.2  3 sf 120.70206  121

Cont. Scientific Notation uses the form, M x 10n M is a number greater than or equal to one but less that 10 n is a whole number 1. Determine M by moving the decimal pt. to the left/right so that only 1 nonzero digit remains to the left of the decimal pt. 2. Determine n by counting the number of places you moved the decimal pt. If you moved it left, n is positive. If you moved it right, n is negative. chemistry deals with very large and very small numbers To make it easier we use scientific notation 0.00087 8.7 x 10-4 9.8 9.8 x 100 23,000,000 2.3 x 107

Temperature TK= TC + 273.15 TC= TK - 273.15 TF= TC • 9/5 + 32 TC = (TF –32) • 5/9 Widely used scales are Fahreheit, celsius, and Kelvin

Density D= m/v States Of Matter 1. Solid fixed volume and shape 2. Liquid  fixed volume, variable shape 3. Gas  variable volume and shape 4. Plasma high temperature physical state in which atoms lose their electrons Plasma is found in a fluorescent bulb

Classification of Matter Pure Substances - made of only one kind of atom or molecule a. Elements- contains only one kind of atom or molecules examples of molecules are N2, O2 b. Compounds- 2 or more elements chemically combined examples: NaCl, CO Nitrogen and oxygen are diatomic Allotrope different forms of an element Example: carbon, graphite, diamond oxygen, ozone

Classification cont. Mixtures - a blend of 2 or more pure substances physically mixed together a. Homogeneous Mixture- uniform in composition also known as a Solution(small particles) Colloid-contains intermediate sized particles b. Heterogeneous Mixture- not uniform throughout Suspension-separates into layers over time Mixtures can be separated physically Cannot be represented by a chemical formula Proportions varies Examples of solutions- tap water, Kool Aid, soda Examples of colloids- milk, gels, foams Examples of suspension- salad dressings, “shake well’

Separation of Mixtures Magnetism Filter Evaporation Centrifuge Decant Chromatography Distillation Density -metal from nonmetal Liquids and particles smaller that filter pores Filtrate- substance collected Liquids evaporates and leaves solid behind Separates matter of different densities Pour off liquid and leave solid behind Separates components of a solution Separates substances with dif. Boiling points Ratio of mass tp volume

Lesson Plans Day 1: Intro. To class: guidelines,books, etc. Individual notes: PHEOC SI base units(7) Dimensional analysis Density

continued States of matter Classification of matter- find handout, define on sheet Separation of mixtures methods Day 2 and 3 Show slides 5-9 HW. P. 33-36: 24,26,28,30,36,48,54,60,68,80

Cont. Day 4 Lab Day 5 Ch. 1 Test