How do you spell that’s French guy’s name? Acids and Bases Do you like Special K? E is for Equilibrium And More Lovely Stuff $100 $100 $100 $100 $100 $200 $200 $200 $200 $200 $300 $300 $300 $300 $300 $400 $400 $400 $400 $400 $500 $500 $500 $500 $500 That French guy’s name #1 • Bromothymol blue (yellow in acidic solution, blue in basic solution) HIn(aq) H+(aq) + In-(Aq) Yellow Blue • Which way will the equilibrium shift if NaOH is added? Le Chateaux Principle? Fe3+(aq) + SCN-(aq) FeSCN2+(aq) Gold colorless Red-brown What will happen if KSCN is added? What will happen if Fe(NO3)3 is added? Le Chatelier’s Again Co(H2O)62+(aq) + 4Cl-(aq) CoCl42-(aq) + 6H2O(l) Pink Blue H= +50 kJ What will happen if: • The solution is cooled • 0.1 M AgNO3(aq) is added • Distilled water is added • Table salt is added Acids and Bases #1 • Which is the weakest acid? • • • • • Acetic acid (HC2H3O2); Ka = 1.8 x 10-5 Hydrocyanic acid (HCN); Ka = 6.2 x 10-10 Benzoic acid (C6H5CO2H); Ka = 6.4 x 10-5 Formic acid (HCHO2); Ka = 1.8 x 10-4 Chlorous acid (HClO2); Ka = 1.2 x 10-2 Acids and Bases #2 • Complete the following reaction: • NH3(aq) + HC2H3O2(aq) • Which is the acid? Which is the base? • Identify the conjugate acid and conjugate base in the reaction. Equilibrium #1 2 SO3 <==> 2 SO2 + O2, Kc = 1.6 x 10-10 At equilibrium, which is true? (a ) The concentrations of both SO2 and O2 will be much larger than the concentration of SO3. (b) The concentrations of both SO2 and O2 will be much smaller than the concentration of SO3. (c) The concentration of O2 will be exactly one half the concentration of SO3. (d) The concentration of O2 will be exactly twice the concentration of SO3. Equilibrium #2 Which box represents the system when it has first reached equilibrium? Acids & Bases #3 • Benzoic acid (C6H5CO2H); Ka = 6.4 x 10-5. What is the pH of a 0.25 M solution of this acid? Equilibrium #3 • The equilibrium constant, Kc, for the reaction SO3(g) + NO(g) NO2(g) + SO2(g) is found to be 5.25 x 10-3 at a certain temperature. If 0.375 mol of SO3 and 0.375 mol of NO are placed in a 2 L container and allowed to react, what will be the equilibrium concentration of each gas? Special K….. Which of the following reactions will form more products (at equilibrium) at the same temperature? Reaction Reaction Reaction Reaction A: K = 1.57 B: K = 0.068 C: K = 235.90 D: K = 3.5 x 102 …or perhaps cornflakes 2A + B 2C + D • If K for the following reaction is 1.55x10-2, and the following initial concentrations are used: [A] = 0.25 M; [B] = 0.37 M; [C] = 0.87 M; [D] = 0.56 M, which way will the reaction have to shift to achieve equilibrium? Other Lovely Stuff • What’s the name of this shameless 2002 ‘Matrix’ rip-off? More Lovely Stuff • Who do you want to win the democratic nomination for this year’s presidential campaign? • Barack Obama • Hilary Clinton • Dennis Rodman • John McCain • David Hasselhoff And still more lovely stuff Very Special K 2A + B C + 2D •Equilibrium Expression? •[A]o = 0.52 M, [B]o = 0.32 M, [C]o = 0.63 M and [D]o = 0.48 M; if [B]e = 0.18 M, what is K for this equilibrium? Kinetics #2 • • • • Consider the reaction: C4H9Br C4H9+ + Br(Slow) C4H9+ + H2O C4H9OH2+ (Fast) C4H9OH2+ + H2O C4H9OH + H3O+ (Fast) • Intermediates? Overall Rate Law? Overall balanced equation? Kinetics #3 • How do catalysts speed up the rate of a reaction? Science on TV #3 • What science fiction-based comedy series are these characters from? Science on TV #4 • In the TV show CSI, one of the tests the scientists use to detect the presence of blood is through the use of a Q-tip and several clear solutions. If a pink color is observed on the Qtip, this is a positive test for blood. • What is the solution they use which gives the pink color? Science on TV #5 • ER: In this show, actors play many roles, including those of people who are employed specifically to draw patients’ blood. • What is the name of this profession? Pick ‘n’ Mix 1 • What are the units for the universal gas constant, R? Pick ‘n’ Mix 2 • A balloon is being inflated. V changes from 3.60 x 104 L to 1.50 x 105 L during inflation, by addition of 0.5 x 105 J of energy (as heat). Balloon expands against external pressure of 1.25 atm. Calculate E for process. (1 L.atm = 101.3 J) Pick ‘n’ Mix 3 • Draw Lewis dot structures for each of the following elements: • C, H, N, O, F and Xe • Extra Credit: What does the number of unpaired electrons tell you about each element? Pick ‘n’ Mix 4 • What is the chemical equation that corresponds to the standard enthalpy of formation (Hf) of perchloric acid, HClO4(l) ? Pick ‘n’ Mix 5 • How many valence electrons are in a molecule of sugar (C6H12O6)?