CHEM 230 LAB EXAM 2 QUESTIONS WITH COMPLETE SOLUTIONS

A) Initial starting solution with brownish yellow correct answer: Fe^3+ A) Initial starting solution with greyish blue correct answer: Cr^3+ A) Initial starting solution with pale green correct answer: Ni^2+ B) So4^2- correct answer: confirmed when precipitate is formed and doesn't dissolve in Nitric acid C) Cl^- correct answer: confirmed when precipitate is dissolved by NH3 D) NO3^- correct answer: confirmed by the brown ring test E) NH4^+ correct answer: confirmed by gas that turns the red litmus --> blue F) Pb^2+ correct answer: confirmed by a heavy black precipitate G) Separation of Fe^3+ and Cr^3+ correct answer: brown precipitate --> H solution --> J H) Fe^3+ correct answer: confirmed by precipitate turning dark blue I) Cr^3+ correct answer: confirmed by a yellow precipitate J) Ca^2+ correct answer: confirmed by a white precipitate (produces a brick red flame in flame test) K) Zn^2+ correct answer: confirmed by a white precipitate that turns blue after heating L) Ni^2+ correct answer: confirmed by a red precipitate Crystal field splitting energy (kJ/mol) correct answer: (6.63X10^-34 J s)(3.00x10^17 nm)(6.022x10^23) / nm (1000KJ) Separation of Pb^2+ correct answer: Pb^2+(aq) + 2Cl^-(aq) --> PbCl2(s) Separation of Fe^3+ and Cr^3+ correct ans