Chem 1B, PAL – Review Worksheet Name: Part A: Titrations 1) Consider the titration of a strong acid with a strong base and the titration of a weak acid with a strong base. In what ways are the titration curves similar? In what ways are they different? 2) In lab, you titrate an unknown monoprotic acid with a NaOH solution from a buret. After adding 12.35 mL of the NaOH, the pH of the solution is 5.22. What is the Ka of the acid if the equivalence point is reached at 24.70 mL? -5 3) You are titrating 25.00 mL of 0.250 M benzoic acid (HC7H5O2, Ka = 6.5 x 10 ) with 0.330 M KOH. a) What is pH at the equivalence point? 1 Chem 1B, PAL – Review Worksheet Part B: Lewis Acids/Bases 4) Draw the Lewis Dot structures and label the following as a Lewis acid or base: a) H2O b) F - c) BH3 d) Fe 3+ 5) Identify the species acting as the Lewis Acid and as well as the species acting as the Lewis Base in the following reaction: 2+ CuSO4(aq) + 4NH3(aq)  [Cu(NH3)4] 2- (aq) + SO4 (aq) 6) List four oxyacids of Cl and identify the oxidation state of each Cl atom. a) Of the four oxyacids listed above, put in order from strongest to weakest acid. b) Of the four oxyacids listed above in question 5, list the conjugate acids in order from strongest to weakest conjugate base. 2 Chem 1B, PAL – Review Worksheet Part B: Solubility 7) Calculate the molar solubility of SrCrO4 in 0.0025 M Na2CrO4(aq). Hint: Check any simplifying assumptions you make to ensure they are valid. 8) A 15.0-g sample of NaI (molar mass = 149.89 g/mol) is dissolved in water to make 0.250 L of -9 2+ solution. The solution is then saturated with PbI2 (Ksp = 9.8 x 10 ). What will be the [Pb ] and [I ] in the saturated solution? - -11 9) Fluoridated drinking water contains about 1 ppm of F . Is MgF2 (Ksp = 5.16 x 10 ) sufficiently - soluble in water to be used as the source of F ions for this fluoridation? Hint: Recall that 1 ppm - 6 signifies 1 g F per 10 g solution and assume that the density of the solution is 1.00 g/mL. 10) A saturated solution of silver chromate has a concentration of [Ag2CrO4] = 7.4 x 10 -5 M. What is the Ksp for the solid compound? 3 Chem 1B, PAL – Review Worksheet Part C: Thermodynamics True or False Liquids have more entropy than their solids Entropy of a substance increases as its temperature increases When solids are dissolved in water, the solutions have more entropy If a chemical reaction is endothermic and spontaneous, then ΔG +, ΔS – and ΔH + Under equal conditions and in the same phase, NO (g) has a greater molar entropy than N2O5 (g). For solid carbon dioxide subliming, entropy < 0 Diluting concentrated sulfuric acid with water can be dangerous. The temperature of the solution can increase rapidly. The signs of ΔrH, ΔrS, and ΔrG for this process are ΔrH < 0, ΔrS > 0, ΔrG < 0 11) Calculate the ΔG° at 25°C for the following reaction: N2O4(g)  2 NO2(g) ΔH° = 58.03 kJ/mol ΔS° = 176.7 J/Kmol 12) At what temperatures will a reaction be spontaneous if ΔrH° = +45 kJ and ΔrS° = +312 J/K? 4