Final Exam Review s5

Chemistry 140 Final Exam Review Spring 2010 The final exam for Chem 140 will be given on Wed, May 5 at 8:30am in our regular classroom, and will be cumulative. The exam will cover chapters 8, 10, 11, 12, 13, 15, and 16 In addition, look at text sections: 3.4, 3.7, 3.8, 7.6, 7.9, 7.11, 7.12, 9.1, 9.3, 23.1 - 23.3, 23.8 The following sections will NOT be covered on the final exam: 8.3 8.4 8.11 8.12 10.5 to 10.10 11.4 through 11.10 12.10, and 12.11 13.3 13.8 13.11 15.6 15.10 15.11 15.15 15.16 16.8 16.9 16.14 16.15 It is particularly important to study and do the problems for the following sections: 8.5 8.8 8.14 10.2 10.4 11.3 12.2 12.4 12.6 13.2 13.5 13.7 15.2 15.8 15.9 15.12 16.3 16.4 16.11 16.13 7.9 7.11 23.2 23.5 Topics that will likely be on the test: converting between moles and grams reaction stoichiometry – calculating theoretical yield Lewis structures for simple molecules electronegativity and polar molecules covalent bonds: polar and non-polar intermol. forces: dipole, H-bonding, London

solution conc. – molarity and mass percent dilution problems (M1V1 = M2V2) Ideal Gas Law: P V = n R T Thermochemistry: given ΔH for a reaction, how much heat is released when 100g of product form? Hess’s Law calculations entropy (ΔS), enthalpy (ΔH), Free Energy (ΔG) effect of temperature and catalyst on reaction rate ΔG = ΔH – TΔS spontaneous (ΔG neg) and non-spont. (Δ G pos) calorimetry: q = m c ΔT (for heating or cooling a substance) q = (moles) x ΔHfusion (for melting) q = (moles) x ΔHvap (for boiling) general Rate Law: rate = k [A]m [B]n reaction order (overall order, order in A or B) initial rates from experimental data (rate = ∆conc/∆time) reaction order from experimental data integrated rate laws: 1st and 2nd order reactions. half-live calculations – first order only reaction mechanisms and elementary steps: unimolecular (1st order), bimolecular (2nd order)

equilibrium expression Kc magnitute of Kc (large Kc means mostly products formed) LeChatelier’s Principle effect of temp on equilibrium (depends on ΔH))

calculations with Qc effect of catalyst on equilibrium (none!)

calculate equilibrium conc. from initial conc. and Kc (use ICE table, do NOT assume x is small) definition of acids/bases:Arrhenius, Bronsted-Lowry pH calculations for strong acids and bases (assume 100% ionization)

conjugate acid/base pairs, converting between Ka and Kb (or pKa and pKb) pH calculations for weak acids and bases (only ~1% ionization) (set up ICE table with initial conc., change in conc, and equilibrium conc. assume x is small) for a weak acid, calculate pH, initial concentration, or Ka effect that various salts will have on the pH of a solution net ionic equation for neutralization reactions aqueous buffer systems and Henderson-Hasselbach equation

Give the Ksp expression for the dissolution of an ionic solid

Ksp calculations for ionic solids dissolved in water ion product (IP) calculations common ion effect (LeChat. principle) orbital hybridization in alkanes hybrid orbitals: sp2 and sp3 electron pair geometry (count atoms + lone pairs) molecular shape (look at atoms only) circle functional groups in a structure drawing proper organic structures

give the molecular formula for a structure alkane formula: Cn H2n+2

Calculations that may be required: ΔG = ΔH – TΔS q = m c ΔT (for heating)

q = (moles) x ΔHfusion (phase change) q = (moles) x ΔHvap (phase change)

ΔHrxn = ΔHf ° products - ΔHff ° reactants

M1 V1 = M2 V2

Rate Equations First Order: Second Order: First Order Half Life: Initial Rate: 1 1 0.693 conc ln[A]t = -kt + ln[A]0  kt  t 1  rate  2 [A]t [A]0 k time

Equilibrium Expression: [C]c[D]d K = from the balanced chemical equation c [A]a[B]b

Ka x Kb = Kw and pKa + pKb = 14 (for acid/conjugate base pairs) pH + pOH = 14 pH = pKa + log(base/acid) (Henderson Hasselbalch)

Know the following

Weak Acids: acetic acid (CH3CO2H) hydrofluoric acid (HF)

Weak Base: ammonia (NH3)

Strong Acids: hydrochloric acid (HCl) nitric acid (HNO3) sulfuric acid (H2SO4) Strong Bases: sodium hydroxide (NaOH) potassium hydroxide (KOH)

Final exam practice problems: see WebAssign and especially old exams!

Skip: PV work, phase diagrams, ΔE, Lewis acids, state functions, bond dissociation energies