Chapter 15 Acids Bases Arrhenius Acid increases H Base increases OH Bronsted Acid donates proton Base accepts Lewis Acid accepts e pair base donates Acid Strength influenced by bond polarity bond strength increases going down a column across a row w of O s decreases w increasing electronegativity Kw 1 0 x 10 14 H OH Kw Ka x Kb If K is small preference for reactants Strong Acids HClO4 H2SO4 HI HBr HCl HNO3 Strong Bases LiOH NaOH KOH Ca OH 2 Sr OH 2 Ba OH 2 H30 10 pH pH log H3O pH pOH 14 Kb HB OH B Chapter 16 Acid Base Equilibrium Buffers Ka H3O A HA of ionization x original conc Small Ka weak acid large Ka strong acid Properties of salt solutions strong acid strong base neutral sltn NaCl weak acid strong base basic sltn NaCN strong acid weak base acidic sltn NH4Cl weak acid weak base depends on Ka vs Kb Buffers resist changes in pH Adding HCl to pure water H3O amount H added total volume Henderson Hasselbach Eqtn pH pKa log B A pKa log Ka Acid Base Titration Curve plot of pH vs amount acid base added Equivalence point mols acid mols base After equiv point VA total volume before VA total volume After EP log cA x vA cB x vB Vtotal Chapter 18 Thermodynamics Equilibrium Entropy S Enthalpy H Free Energy G S q T eqlbm S Hvap T 3rd law a perfect crystalline 0K has entropy of 0 Entropy increases when S q T rxn spontaneous G T H T S rxn in which a molecule is broken down into 2 rxn in which there is an increase in mols of gas a process in which solid gas liquid or liquid gas S nS products mS reactants G nG f products mG f reactants Wmax G G H T S When G is large rxn is spontaneous and proceeds G is large rxn is nonspontaneous G is small or rxn is eqlbm G RT ln K R 8 31 J mol K G G RT ln Q Effect of Temp on Rxn Spontaneity H H H Description to find temp at qhich a rxn becomes spontaneous Spont all temps Non all temps Spont low non high Non lol spont high G solve for T H S Chapter 14 Chemical Equilibrium Kp Kc RT n n change in mols of gas R gas constant 08206 Latm molK When Kc 1 nearly all products eqlbm Kc 1 mixture of both Kc 1 nearly all reactants eqlbm Q vs K Qc Kc the rxn goes to left more reactants Qc Kc the rxn eqlbm Qc Kc the rxn goes to right more products do not omit H2O for Kc only Ka or Kb don t forget about coefficients as exponents in K s Chapter 14 Chemical Equilibrium cont 3 ways to alter eqlbm 1 change conc by removing products or adding reactants 2 change the partial pressures by changing volume 3 change the temp if P is increased by decreasing V rxn shifts in direction of fewer gas molecules for endo rxn incr temp incr of Products exo rxn decr temp incr react a catalyst has no effect on eqlbm only increases speed of rxn heterogeneous eqlbm omit solids Chapter 19 Electrochemistry Faraday s Constant 1F 96485 C 1 mol e 1AS 1C 1s W F potential difference units J C V Red Cat reduction occurs at cathode Wmax nFEcell where n moles of e F Faraday s constant Ecell Ecathode Eanode Ecell RT ln K nF G nFEcell G nFEcell Voltaic Cells spontaneous Ecell e flow toward cathode cations flow toward cathode anions flow toward anode to determine initial voltage solve for Ecell to determine voltage after X amps for Y hours Ecell 0592 n log K Ecell Ecell 0592 n log K change Y to seconds then convert to C to mol e to mol ions consumed D then find new conc reactant ion consumed original D then find new conc product ion produced original D to determine how long battery can deliver Z amps before going dead change original mol ion consumed to mol e to Z C to seconds to determine the cell potential when the conc of X ion falls to Y amount determine new Q but make sure you add the difference of the change from the original top conc ex 1 5 M Cu2 05 M Pb2 Cu2 falls to 2 M difference 1 5 x 2 so x 1 3 new Q 05 1 3 2 1 35 2 aqueous electrolysis what might occur anode what might occur cathode Chapter 17 Solubility Complex Ion Equilibrium Molar solubility mols of ionic compound that dissolve to give 1L of saturated sltn X from ICE tables tells you molar solubility to calc molar solubility in a different ion ex calc MS of CuSO4 in NaCN determine overall eqtn break it up into 2 steps Kf x Ksp Kc Ksp x Kf the smaller the Ksp the more insoluble Criterion for Precipitation if Qc Kc a precipitate forms if Qc Kc rxn is eqlbm if Qc Kc no precipitate forms Fractional Precipitation product w larger Ksp will precipitate first min conc to trigger precipitation solve for Q Ksp Complex Ion Equilibria Kf formation constant Kd dissociation constant to determine if a precip will form in a complex ion Kd 1 Kf rearrange to Kd format the init conc on the right will be given amount 2x the final amount ex will precip form from 010 M AgNO3 1 M NH3 Ag NH3 2 Ag 2NH3 01 0 1 2x 01 98 Amphoteric hydroxides metal hydroxide that reacts w both acids and bases Ex Zn2 Al3 Cr3 Pb2 Sn2 Sn4 to determine if a precip will form when 2 volumes molarities are given find new conc of both ions by dividing by total volume then solve for Q Separation of Metal Ions by Sulfide Precipitation determine which precipitates first larger Ksp determine sulfide conc which will trigger 1st precipitate Q Ksp Chapter 20 Nuclear Chemistry Methods of Radioactive Decay Alpha Emission a 4 Beta Emission an electron is ejected 2He nucleus is ejected Positron Emission a proton is ejected Electron Capture Gamma Emission release of energy Spontaneous Fission an unstable nucleus splits into 2 separate ones Chapter 13 Kinetics cont to determine how long until A decays to 12 5 3 half lives solve for half life and multiply by 3 for 1st order rxns for other orders calc regular half lives then the next one using new A 0 if given A 0 2M how long until the conc reaches 015M A t 015M use integrated rate law and solve for t don t write rate laws in terms of intermediates choose one intermediate to solve for and substitute combine all k s together Effect of Catalysts don t change overall H only lowers Ea to determine rate law from initial rates of trials compare exp 1 to 2 exp 1 to 3 and exp 1 to 4 solve for each exponent m n p Chapter 23 Organic Chemistry carbon makes 4 bonds but only …