Spring 2019, CHEM 102– Dr. Collins Tuesday: 6:30 – 7:30, ZACH 340SI Leader – Nikhil Manuel Wednesday: 6:30 – 7:30, ZACH [email protected] Thursday: 6:30 – 7:30, ZACH 340https://sites.google.com/tamu.edu/sichemistry102/homeSI Session – EXAM 3 REVIEW (4/13/19)Chapter 14 – Buffers- Conceptual Reviewa.) What is necessary for a buffer solution? How is this influenced by the common ioneffect?b.) Write the two variations of the Henderson-Hasselbach equation. c.) What types of indicators should you use for each titration? d.) Write the methodology for each titration type. 1.) SA/SB titration 2.) WA/SB titration 3.) WB/SA titration© Texas A&M University, Academic Success CenterSpring 2019, CHEM 102– Dr. Collins Tuesday: 6:30 – 7:30, ZACH 340SI Leader – Nikhil Manuel Wednesday: 6:30 – 7:30, ZACH [email protected] Thursday: 6:30 – 7:30, ZACH 340https://sites.google.com/tamu.edu/sichemistry102/home- Practice Problemsa.) Calculate the pH of … 1.) A buffer solution consisting of 0.50 M CH3COOH and 0.50 M CH3COONa. Thencalculate the pH2.) After adding 0.020 moles of solid NaOH to 1.0 L of the buffer solution in part (1)3.) After adding 0.020 moles of HCl to 1.0 L of the buffer solution in part (1)b.) An environmental chemist needs a carbonate buffer of pH 10.00 to study the effectsof the acid rain on limestone-rich soils. How many grams of Na2CO3 must she add to1.5 L of freshly prepared 0.20 M NaHCO3 to make the buffer? Ka of HCO3- is 4.7  10-11© Texas A&M University, Academic Success CenterSpring 2019, CHEM 102– Dr. Collins Tuesday: 6:30 – 7:30, ZACH 340SI Leader – Nikhil Manuel Wednesday: 6:30 – 7:30, ZACH [email protected] Thursday: 6:30 – 7:30, ZACH 340https://sites.google.com/tamu.edu/sichemistry102/homec.) Calculate the pH during the titration of 40.00 mL of 0.1000 M propanoic acid afteradding the following volumes of 0.1000 M NaOH 1.) 0.00 mL 2.) 30.00 mL 3.) 40.00 mL 4.) 50.00 mL d.) Consider the titration of 100.0 mL of 0.200 M CH3NH2 by 0.100 M HCl. Calculatethe pH. (Kb for CH3NH2 = 4.4 x 10-4)1.) after 0.0 mL of HCl added. 2.) after 20.0 mL of HCl added. 3.) after 65.0 mL of HCl added. 4.) at the equivalence point. 5.) after 300.0 mL of HCl added. 6.) what volume of HCl added does the pH = 10.643© Texas A&M University, Academic Success CenterSpring 2019, CHEM 102– Dr. Collins Tuesday: 6:30 – 7:30, ZACH 340SI Leader – Nikhil Manuel Wednesday: 6:30 – 7:30, ZACH [email protected] Thursday: 6:30 – 7:30, ZACH 340https://sites.google.com/tamu.edu/sichemistry102/homeChapter 15 – Solubility- Conceptual Reviewa.) What is the general set up for a solubility question, and the Ksp expression? b.) What is the difference between solubility and molar solubility? c.) How can the common ion effect affect solubility? d.) What is a complex ion? How is the Kf represented?- Notesa.) The ion that surrounds a complex ion is a ligandb.) Ligand increases solubility of a slightly soluble ionic compound if it forms a complexion c.) pH can affect solubility, observe slide 23 of Chapter 15 notesd.) In a basic compound, lowering the pH can draw out the hydroxide, making the compound more soluble. Vice versa for an acidic solution © Texas A&M University, Academic Success CenterSpring 2019, CHEM 102– Dr. Collins Tuesday: 6:30 – 7:30, ZACH 340SI Leader – Nikhil Manuel Wednesday: 6:30 – 7:30, ZACH [email protected] Thursday: 6:30 – 7:30, ZACH 340https://sites.google.com/tamu.edu/sichemistry102/home- Practice Problems a.) Lead (II) sulfate is a key component in lead-acid car batteries. Its solubility in water at 25˚C is 4.25  10-3 g/100 mL solution. What is the Ksp? (19.5)b.) When lead (II) fluoride is shaken with pure water at 25˚C, the solubility is found to be0.64 g/L. Calculate the Ksp. c.) Calculate the solubility of Ca(OH)2 in water if the Ksp is 6.5  10-6. (19.6)d.) In relation to the previous question, what is its solubility in 0.10 M Ca(NO3)2?© Texas A&M University, Academic Success CenterSpring 2019, CHEM 102– Dr. Collins Tuesday: 6:30 – 7:30, ZACH 340SI Leader – Nikhil Manuel Wednesday: 6:30 – 7:30, ZACH [email protected] Thursday: 6:30 – 7:30, ZACH 340https://sites.google.com/tamu.edu/sichemistry102/homee.) Which of the following will in increase in solubility with addition of acid? 1.) Lead (II) Bromide 4.) Calcium Fluoride2.) Copper (II) Hydroxide 5.) Zinc Sulfide3.) Iron (II) Sulfide 6.) Silver Iodide (19.8)f.) Does a precipitate form when 0.100 L of 0.30 M Ca(NO3)2 is mixed with 0.200 L of 0.060 M NaF? Ksp of CaF2 is 3.2  10-11. (19.9)g.) An industrial chemist converts Zn(H2O)42+ to the more stable Zn(NH3)42+ by mixing 0.50 L of 0.0020 M Zn(H2O)42+ and 25.0 L of 0.15 M NH3. What is the final concentration of Zn(H2O)42+? Kf of Zn(NH3)42+ is 7.8  108. (19.10)© Texas A&M University, Academic Success CenterSpring 2019, CHEM 102– Dr. Collins Tuesday: 6:30 – 7:30, ZACH 340SI Leader – Nikhil Manuel Wednesday: 6:30 – 7:30, ZACH [email protected] Thursday: 6:30 – 7:30, ZACH 340https://sites.google.com/tamu.edu/sichemistry102/homeChapter 17 – Electrochemistry - Conceptual Reviewa.) When writing a redox reaction, what is the order for balancing in acidic solutions? What about basic solutions? b.) What is the oxidation states rules that are common? c.) EO cell is calculated how? - Notesa.) View Dr. Collins notes for clarification. b.) When in acidic solutions, there should be H+. In basic solutions, there should be OH-.This makes sense in regards to the environment. c.) Anode is oxidized; cathode is reduced.d.) ∆G = -nFEcell and ∆Go = -nFEocell , with n = number of moles of electrons in reactione.) F is Faradays constantf.) Eocell = (RT/nF)  lnK = (0.0592 V/n)  logK© Texas A&M University, Academic Success CenterSpring 2019, CHEM 102– Dr. Collins Tuesday: 6:30 – 7:30, ZACH 340SI Leader – Nikhil Manuel Wednesday: 6:30 – 7:30, ZACH [email protected] Thursday: 6:30 – 7:30, ZACH 340https://sites.google.com/tamu.edu/sichemistry102/home- Practice Problemsa.) MnO4¯ + S2O32¯ → Mn2+ + SO42¯ ; balance in acidic conditionsb.) NO3¯ + S2¯ → S8 + NO2 ; balance in acidic conditions© Texas A&M University, Academic Success CenterSpring 2019, CHEM 102– Dr. Collins Tuesday: 6:30 – 7:30, ZACH 340SI Leader – Nikhil Manuel Wednesday: 6:30 – 7:30, ZACH [email protected] Thursday: 6:30 – 7:30, ZACH