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Chapter 1 Chemical Foundations HW: p. 32-35, #’s 26, 28, 30, 36, 50, 54, 56, 68 Fundamental SI Units Physical Property Mass Length Time Temperature Electric current Amount of substance Luminous intensity Name of Unit kilogram meter second Kelvin ampere mole candela Abbreviation kg m s K A mol cd Common Prefixes Used in the SI System Prefix Mega Kilo Hecto Deca _____ Deci Centi Mili Micro Nano Symbol M k h da __ d c m µ n Exp Notation 106 103 102 101 ___ 10-1 10-2 10-3 10-6 10-9 Significant Figure Rules - Counting 1. ALL non-zero numbers count a. 5485 has 4 sig figs 2. leading zeros NO NOT count a. 0.0025 has 2 sig figs 3. captive zeros between nonzero numbers COUNT a. 1.008 has 4 sig figs 4. Trailing zeros count ONLY if the number contains a decimal point. a. 100 has only 1 sig fig Significant Figure Rules – Mathematical Operations 1. multiplication and division a. number of sig figs in the answer is the same as the least precise number in the calculation. i. 93.45 x 13.2 = answer will have 3 sig figs 2. addition and subtraction a. number of sig figs in the answer will be the number of decimal places in the least precise number in the calculation. i. 34.32 + 18.1 + 2.075 = answer will have 1 decimal place Significant Figure Rules – Rounding 1. When performing calculations that involve multiple steps, perform all calculations and round to the correct number of sig figs AT THE END Dimensional Analysis 1. To convert from one unit to another, use the equivalence statement that related the two units. 2. Derive the correct unit factor by looking at the direction of the required change so you cancel unwanted units. 3. Multiply the quantity to be converted by the unit factor to give the quantity with the desired units. = Mass per unit volume Remember mL = cm3 States of Matter Solid Liquid Gas Mixtures Combinations of pure substances May be……… √ Homogeneous – visibly indistinguishable parts √ Heterogeneous – visibly distinguishable parts Filtration – separation of a liquid and a solid Distillation - separates due to the difference in the volality of the substances Chromatography – separates components by their affinity to the mobile or stationary phase
