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Summary Chapter 1 - 4 Chemistry: The Molecular Nature of Matter, 6th edition By Jesperson, Brady, & Hyslop CH 1-4 Concepts to be Familiar With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quations & Conversions to Memorize Unit Conversions Equations For metric units (m, kg, s, K, mole): mega (M) 106 kilo (k) 103 centi (c) 10-2 milli (m) 10-3 micro (µ) 10-6 nano (n) 10-9 Pico (p) 10-12 Density = mass / Volume d = m/V dH2O = 1 g/mL = 1 g/cm3 Molecular Mass (MM) = Molecular Weight (MW)= mass/moles MM = m/n NA = 6.022 x 1023 particles/mole MMmolecule = ! MMatoms in molecules Time conversions: d"hr"m"s 1 mL = 1 cm3 T(kelvin) = T(°C) + 273.15 °F = 1.8°C +32 Elements & Molecules A Z X Elements on the Periodic Table X = Element symbol (ie O = oxygen) A = Isotope Mass Number = # protons + # neutrons Z = Atomic Number = # protons atomic number M+ !+ element symbol NOPQN+ atomic weight (amu) = weighted average of atomic weight of isotopes Emperical Formula: AxBy Ex: CH3O Molecular Formula: An ! xBn ! y Ex: C2H6O2 Structural Formula: AwAxBz Ex: HOCH2CH2OH Drawing Molecules: Methane CH4 H H C H H Chemical Equations aA (physical state) + bB (state) " cC (state) + dD (state) (physical state) = solid (s), liquid (l), gas (g), aqueous (aq) A, B = reactants C, D = reactants a, b, c, d = coefficients to indicate molar ratios of reactants and products Balancing Chemical Equations: Unbalanced equation: C4H10 + O2 !" CO2 + H2O Balanced equation: !!2C4H10 2 molecules of C4H10 + 13O2 !" 8CO2 + 10H2O 13 molecules of O2 8 molecules of CO2 10 molecules of C4H10 Significant Figure Rules R+ J'%/*(&'+')*C/*()*1+?""+;%9%5$+%*+-/#$30/-/*5+32+5)+#*;+ %*'"3;%*9+&0$5+/$(-#5/;+;%9%5+#0/+$%9*%&'#*5P+ 1. All non-zero numbers are significant. 2. Zeros between non-zero numbers are significant. 3. Trailing zeros always count as significant if number has decimal point 4. Final zeros on number without decimal point are NOT significant 5. Final zeros to right of decimal point are significant 6. Leading zeros, to left of first nonzero digit, are never counted as significant Rounding Guidelines: 1. If digit to be dropped is greater than 5, last remaining digit is rounded up. 2. If number to be dropped is less than 5, last remaining digit stays the same. 3. If number to be dropped is exactly 5, then if digit to left of 5 is a. Even, it remains the same. b. Odd, it rounds up. Multiplication/Division & Addition/Subtraction: 1. Multiplication/Division: the number of significant figures in answer = number of significant figures in least precise measurement 2. Addition/Subtraction: the answer has same number of decimal places as quantity with fewest number of decimal placesP Molecules: Ionic Compounds Ions Transfer of one or more electrons from one atom to another Form electrically charged particles Ionic compound Compound composed of ions Formed from metal and nonmetal Properties Conducts electricity in liquid state when ions are free to move, but not as a solid Nomenclature: Cation (charge) Anion-ide ie: Iron (II) Oxide = FeO Fe2+ O2Sodium Chloride = NaCl Na+ Cl- Criss-cross rule # Make magnitude of charge on one ion into subscript for other # When doing this, make sure that subscripts are reduced to lowest whole number. Al3+ O2– Al2O3 Molecules: Ionic Compounds Molecules: Covalent Compounds Molecules Nonmetal hydrides # Molecule containing nonmetal + hydrogen # Number of hydrogens that combine with nonmetal = number of spaces from nonmetal to noble gas in periodic table # Electrically neutral particle # Consists of two or more atoms # Covalent compounds have nonmetal-nonmetal bonds Chemical bonds # Attractions that hold atoms together in molecules # Arise from sharing electrons between two atoms Naming Binary Molecular Compounds # Group of atoms that make up molecule behave as single particle Molecular formulas # Describe composition of molecule # Specify number of each type of atom present – First element in formula • Use English name – Second element # Use stem and append suffix –ide # Use Greek number prefixes to specify how many atoms of each element Nomenclature Overview for Reference Mole Ratios Mole Ratios Within Molecules: AxBy Mole ratio of A:B = x:y Mole Ratios Between Molecules: aA + bB " cC + dD Mole ratio of A:B:C:D = a:b:c:d Percent Composition & Empirical Formulas Percent Composition (experimental or theoretical): Calculate percentage by mass of each element in sample (mass element) / (total mass of sample) x 100% Empirical Formula Simplest ratio of atoms of each element in compound Obtained from experimental analysis of compound • E,+/-2%0%'#"+,)0-3"#+%$+!"#$!! • + D)"/'3"#0+,)0-3"#+=%""+4/+!%&"!"#%&"!$& Molecular Formula Need molecular mass and empirical formula Calculate ratio of molecular mass to mass predicted by empirical formula and round to nearest integer n= molecular mass empirical formula mass Stoichiometry aA + bB mass A x÷ MM moles A mass B + mass C x÷ MM a:b cC " mass D x÷ MM moles B b:c moles C dD x÷ MM c:d moles D a:c a:d Limiting Reactant: • Least # moles after equalize with mole ratio • Use limiting reactant to determine amount of product ! actual yield $ && ' 100% percentage yield = ## " theoretical yield % Stoichiometry