CHEM 116 Exam 3 Practice Test Qs&As 2024

CHEM 116 Exam 3 Practice Test Qs&As 2024 Which of the following combinations cannot produce a buffer solution? - ANS-HNO3 and NaO3 Consider an indicator (kHIn= 6.3 x 10^-6) that ionizes as shown below. Which of the following statements is true? HIn + H20 (yellow) <----> H3O+ +In- (blue) - ANS-In acidic solutions containing the indicator, we would expect predominantly yellow color Which of the following solubility product expressions is correct? - ANS-AuI, ksp= [Au+][I-] In the titration curve shown below, which point represents the pH of a buffer solution? - ANS-II The plot on right shows a titration curve for the titration of 1.00 L of 1.00M diprotic acid H2A with NaOH. A buffer region is indicated by which point(s) a-d? - ANS-points a and c The following pictures represent so-lutions that contain a weak acid HA (pKa = 5.0) and its potassium salt KA. Unshaded spheres represent H atoms and shaded spheres represent A- ions. (K+, H3O+, OH-, and solvent H2O molecules have been omitted for clar-ity.) Which of these solutions are buffers? - ANS-All are buffer solutions The following pictures represent solutions at various points in the titration of a weak acid HA with aqueous KOH. Unshaded spheres represent H atoms, black spheres represent oxygen atoms, and shaded spheres represent A- ions. (K+, H3O+ initially present, OH- initially present and sol-vent water molecules have been omitted for clarity). Which picture represents the solution just before the equivalence point? - ANS-2 Calculate the Ksp for silver sulfite if the solubility of Ag2SO3 in pure water is 4.6 × 10-3 g/L. - ANS-1.5 x 10^-14 In which one of the following is the oxidation state of nitrogen given incorrectly? - ANS-HNO2 (+5) In the following, which species is reduced? 3Ag2S(s) + 8H+(aq) + 2NO3-(aq) 6Ag+ (aq) + 3S(s) + 2NO(g) + 4H2O - ANS-NO3- The Gibbs free energy equation is given by - ANS-deltaG= deltaH - TdeltaS What are the coefficients in front of BrO3-(aq) and Br-(aq) when the following equation is balanced in an acidic solution: ___ BrO3-(aq) + ___ Br-(aq) → ___ Br2(aq)? - ANS-1, 5 Given the following values of Ksp for four slightly soluble sulfides at 25°C. Which one of the following ions exists in the highest concentration in a solution in which the sulfide ion concentration had been fixed at some (fairly large constant value, at 25°C? - ANS-Mn+ The Ksp for Fe(IO3)3 is 10-14. We mix two solutions, one containing Fe3+ and one containing IO3- ions at 25°C. At the instant of mixing, [Fe3+] = 10-2 M and [IO3-] = 10-3 M. Which one of the following statements is true? - ANS-A precipitate forms, because Qsp > Ksp Using the following portion of the activity series for oxidation half reactions: Continues...