Exam 3 - Chem 1520 Questions And Answers

Exam 3 - Chem 1520 Questions And Answers acid-base indicator - ANS-a weak organic acid whose color differs from that of its conjugate base pH - ANS-the color of an indicator changes over a specific, narrow ____ range, a range of about 2 units neutralizing - ANS-in an acid-base titration, the concentration of an acid (or a base) is determined by _________________ the acid (or base) with a solution of a base (or acid) of a known concentration equivalence - ANS-The ______________ point of the reaction occurs when the number of moles of OHadded equals the number of moles of H3O+ originally present, or vice versa end - ANS-The ________ point occurs when the indicator changes color. The indicator should be selected so that its color change occurs at a pH close to that of the equivalence point. 1.) 1.00 2.) 1.269 3.) 7 4.) 12.22 - ANS-50.0 mL of 0.100 M HCl is titrated with 0.100 M NaOH. 1. Calculate the initial pH. 2. Calculate the pH after 15.0 mL NaOH is added. 3. Calculate the pH after 50.0 mL NaOH is added. 4. Calculate the pH after 70.0 mL of NaOH is added. 1.) 2.87 2.) 4.14 3.) 4.74 4.) 8.72 5.) 11.959 - ANS-Problem: 50.0 mL of 0.100 M CH3COOH is titrated with 0.100 M NaOH. Ka (CH3COOH) = 1.8 x 10-5 1. Calculate the initial pH. 2. Calculate the pH after 10.0 mL NaOH is added. 3. Calculate the pH at the midpoint of the titration. 4. Calculate the pH at the equivalence point. 5. Calculate the pH after 60.0 mL NaOH is added. 1.) 11.13 2.) 9.52 3.) 9.26 4.) 5.28 5.) 1.95 - ANS-100.0 mL of 0.100 M NH3 is titrated with 0.100 M HCl. Kb = 1.8 x10-5 1. Calculate the initial pH. 2. Calculate the pH after 35.0 mL HCl is added. 3. Calculate the pH at the midpoint of the titration. 4. Calculate the pH at the equivalence point. 5. Calculate the pH after 125.0 mL HCl is added. polyprotic acid - ANS-the amino acid behaves like a ______________ _______ insoluble - ANS-any "__________" ionic compound is actually slightly soluble in aqueous solution. We assume that the very small amount of such a compound that dissolves will dissociate completely. 1.0*10^-5 (M) - ANS-Calculate the molar solubility of BaSO4 given Ksp = 1.1 x 10-10. CONTINUES...