Chem : Feb.12-17

Transcription

1 Chem : Feb.2-7 Preparation Pre-lab Report (p.90) for E3 completed Discussion Presentation for E2 completed Pre-lab reading and studies for E3 completed Lab Agenda One hour discussion of E 2(Questions, p.73) Two hours of E3; E3= two session 5 hour lab E3: Redox: Transferring Electrons Session : Two our Lab Agenda* Complete Part Complete Part 2A Complete Team Report (Parts and 2A) * See Student Information Sheet on Ctools under Resources Experiments. Session 2: Three our Lab Agenda # Complete Parts 2B and 3 # Note: TeamReports due post spring break E3 Redox: Transferring Electrons Redox = oxidation-reduction Redox reactions involve electron transfer.

2 Loss of electrons (LEO) = oxidation Gain of electrons (GER) = reduction A VIIIA 2 e s IIA IIIA IVA VA VIA VIIA s 2 3 Li 4 Be 5 B 6 C 7 N 8 O 9 F 0 Ne 2s 2s 2 2s 2 2p 2s 2 2p 2 2s 2 2p 3 2s 2 2p 4 2s 2 2p 5 2s 2 2p 6 Na 3s 9 K 4s 37 Rb 5s 55 Cs 6s 87 Fr 7s 2 Mg 3 Al 4 Si 5 P 6 S 7 Cl 8 Ar 3s 2 IIIB IVB VB VIB VIIBVIIIB! VIIIB IB IIB 3s 2 3p 3s 2 3p 2 3s 2 3p 3 3s 2 3p 4 3s 2 3p 5 3s 2 3p Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 4s 2 3d 4s 2 3d 2 4s 2 3d 3 4s 2 3d 5 4s 3d 5 4s 2 3d 6 4s 2 3d 7 4s 2 3d 8 4s 2 4s 2 4p 4s 2 4p 2 4s 2 4p 3 4s 2 4p 4 4s 2 4p 5 4s 2 4p 6 3d 0 4s 3d 0 4s 2 38 Sr 5s 2 56 Ba 6s 2 88 Ra 7s Y Zr Nb Mo Tc Ru Rh Pd 4d 5s 2 4d 2 5s 2 4d 3 5s 2 4d 5 5s 4d 5 5s 2 4d 7 5s 4d 8 5s 4d 0 57 La* 5d 6s 2 Background Information: Redox Metals lose electrons (LEO) Non-metals gain electrons GER) 47 Ag 4d 0 5s 48 Cd 4d 0 5s 2 49 In 50 Sn 5 Sb 52 Te 53 I 54 Xe 5s 5p 5s 5p 2 5s 5p 3 5s 5p 4 5s 2 5p 5 5s 5p 6 72 f 73 Ta 74 W 75 Re 76 Os 77 Ir 78 Pt 79 Au 80 g 8 Tl Bi 84 Po 85 At 86 Rn 5d 2 6s 2 5d 3 6s 2 5d 4 6s 2 5d 5 6s 2 5d 6 6s 2 5d 7 6s 2 5d 9 6s 6s 2 6p 6s 2 6p 2 6s 2 6p 3 6s 2 6p 4 6s 2 6p 5 6s 2 6p 6 5d 0 6s 5d 0 6s Element synthesized, Ac # but no official name assigned 6d 7s 2 6d 2 7s 2 6d 3 7s 2 6d 4 7s 2 6d 5 7s 2 6d 6 7s 2 6d 7 7s 2 + Q. Max positive oxidation state of family A metal ions? A VIIIA +2 2 s IIA 3 4 Li Be 2s 2s 2 Q. Oxidation states of Sn? Sn = 0 or VIIA IIIA IVA VA VIA 2 3 3s 3s VIIIB 9 0 IIIB IVB VB VIB VIIB! VIIIB 2 Al IB IIB 3s 2 3p K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge 4s 4s 2 4s 2 3d 4s 2 3d 2 4s 2 3d 3 4s 3d 5 4s 2 3d 5 4s 2 3d 6 4s 2 3d 7 4s 2 3d 8 4s 3d 0 4s 2 3d 0 4s 2 4p 4s 2 4p Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb 5s 5s 2 5s 2 4d 2 5s 2 4d 2 5s 2 4d 3 5s 4d 5 5s 2 3d 5 5s 4d 7 5s 4d 8 4d 0 5s 4d 0 5s 2 4d 0 5s 2 5p 5s 2 5p 2 5s 2 5p Cs Ba La* f Ta W Re Os Ir Pt Au g Tl Bi Po 6s 6s 2 6s 2 5d 6s 2 5d 2 6s 2 5d 3 6s 2 5d 4 6s 2 4d 5 6s 2 5d 6 5d 7 6s 2 6s 5d 9 6s 5d 0 6s 2 5d 0 6s 2 6p 6s 2 6p 2 6s 2 6p 3 6s 2 6p Element synthesized, Fr Ra Ac # s 7s 2 7s 2 6d 7s 2 6d 2 7s 2 7d 3 7s 2 6d 4 7s 2 3d 5 6s 2 6d 6 6d 7 7s 2 but no official name assigned

3 A 2 s IIA 3 4 Li Be 2s 2s !!!!! Al 3s 3s 2 IIIB IVB VB VIB VIIB VIIIB " VIIIB IB IIB 3s 2 3p 9 K 4s 20 Ca 4s 2 2 Sc 4s 2 3d Ti V Cr Mn Fe Co Ni Cu 4s 2 3d 2 4s 2 3d 3 4s 3d 5 4s 2 3d 5 4s 2 3d 6 4s 2 3d 7 4s 2 3d 8 4s 3d Rb Sr Y 40 Zr 4 Nb 42 Mo 43 Tc 44 Ru 45 Rh 46 Pd 5s 5s 2 5s 2 4d 5s 2 4d 2 5s 2 4d 3 5s 4d 5 5s 2 3d 5 5s 4d 7 5s 4d 8 4d 0 55 Cs 6s 87 Fr 7s 56 Ba 6s 2 Transition Metals Q. Maximum oxidation state vs. family #? 47 Ag 5s 4d 0 30 Zn 4s 2 3d IIIA IVA VA 3 Ga 4s 2 4p 32 Ge 4s 2 4p 2 48 Cd 5s 2 4d 0 49 In 50 Sn 5 Sb 5s 5p 5s 5p 2 5s 5p 3 6 VIA La* f Ta W Re Os Ir Pt Au g Tl Bi Po 6s 2 5d 6s 5d 6s 5d 3 6s 5d 6s 4d 6s 5d 6 5d 6s 2 6s 5d 6s 2 6p 6s 2 6p 2 6s 2 6p 3 6s 2 6p s 5d 0 6s 2 5d Element synthesized, Ra Ac # but no official name assigned 7s 2 7s 2 6d 7s 2 6d 2 7s 2 7d 3 7s 2 6d 4 7s 2 3d 5 6s 2 6d 6 6d 7 7s 2 7 VIIA 8 VIIIA Redox Reactions Example: 2 Na + Cl 2 2 NaCl + energy LEO GER DEMO Redox Reactions Reactants transfer electrons. Reactants change charge (oxidation state). 2 Na (s) + Cl 2 (g) 2 NaCl (s) Lose of e s = oxidation (Na Na + in NaCl) Gain of e s = reduction (Cl Cl - in NaCl)

4 REDOX alf Reactions Oxidation Reduction ( > in oxidation state) ( < in oxidation state) 2 ( Na Na+ + e- ) ( Cl 2 + 2e- 2Cl - ) alf rxns always written to show electron GAIN. The equation = the sum of the half reactions where electrons lost = electrons gained: 2 Na + Cl 2 2 Na Cl - OXIDIZING AGENT Gains electrons and is reduced (GER) REDUCING AGENT Loses electrons and is oxidized (LEO) Oxidizing agents cause the oxidation of other substances. Reducing agents cause the reduction of other substance. Q. Label the reducing agent (RA) and oxidizing agent (OA) in the reaction: 2 Na + Cl 2 2 Na Cl - + energy

5 Reducing and Oxidizing Agent Strength The stronger RA and OA = reactants The weaker RA and OA = products 2 Na + Cl 2 2 Na Cl - RA OA OA RA Strength of oxidizing agents: > Q. Based on the reaction below between Na and Cl 2, compare sodium metal and chloride ion as reducing agents (RA) 2 Na + Cl 2 2 Na Cl - + energy RA OA OA RA a) Cl - > Na b) Na > Cl - c) Cl 2 > Na + d) Na + > Cl - Metal IONS from IA, IIA and IIB = oxidizing agents + A s 3 Li 2s Na 3s 9 K 4s 37 Rb 5s 55 Cs 6s 87 Fr 7s +2 IIA 4 Be 2s 2 2 Mg 3s 2 20 Ca 4s 2 38 Sr 5s 2 56 Ba 6s 2 88 Ra 7s 2 +2 IIIB IVB VBVIBVIIBVIII! VIIIB IB IIB Sc 3d 4s 2 39 Y 4d 5s 2 Example: Zn e - Zn Ti V Cr Mn Fe 3d 2 4s 2 3d 3 4s 2 3d 5 4s 3d 5 4s 2 3d 6 4s Zr Nb Mo Tc Ru 4d 2 5s 2 4d 3 5s 2 4d 5 5s 4d 5 5s 2 4d 7 5s 27 Co 3d 7 4s 2 45 Rh 4d 8 5s La* f Ta W Re Os Ir 5d 6s 2 5d 2 6s 2 5d 3 6s 2 5d 4 6s 2 5d 5 6s 2 5d 6 6s 2 5d 7 6s Ac # d 7s 2 6d 2 7s 2 6d 3 7s 2 6d 4 7s 2 6d 5 7s 2 6d 6 7s 2 6d 7 7s 2 28 Ni 3d 8 4s 2 46 Pd 4d 0 78 Pt 5d 9 6s 29 Cu 3d 0 4s 47 Ag 4d 0 5s 79 Au 5d 0 6s 30 Zn 3d 0 4s 2 48 Cd 4d 0 5s 2 80 g 5d 0 6s 2 VIIIA 2 e s IIIA IVA VA VIAVIIA B C N O F Ne 2s 2 2p 2s 2 2p 2 2s 2 2p 3 2s 2 2p 4 2s 2 2p 5 2s 2 2p 6 3 Al 3s 2 3p 3 Ga 4s 2 4p 49 In 5s 2 5p 8 Tl 6s 2 6p + Element synthesized, but no official name assigned 4 Si 3s 2 3p 2 32 Ge 4s 2 4p 2 50 Sn 5s 2 5p s 2 6p 2 5 P 3s 2 3p 3 33 As 4s 2 4p 3 5 Sb 5s 2 5p 3 83 Bi 6s 2 6p 3 6 S 3s 2 3p 4 34 Se 4s 2 4p 4 52 Te 5s 2 5p 4 84 Po 6s 2 6p 4 7 Cl 3s 2 3p 5 35 Br 4s 2 4p 5 53 I 5s 2 5p 5 85 At 6s 2 6p 5 8 Ar 3s 2 3p 6 36 Kr 4s 2 4p 6 54 Xe 5s 2 5p 6 86 Rn 6s 2 6p 6

6 Metal IONS outside family IA, IIA and IIB with multiple oxidation states = oxidizing or reducing agents 8 A VIIIA s IIA IIIA IVA VA VIA VIIA 3 4 Li Be 2s 2s 2 +2! +2! +2! +2! +2! s 3s VIIIB IIIBIVBVB VIB VIIB " VIIIB IB 9 K 4s Ca Sc Ti V Cr Mn Fe 4s 2 4s 2 3d 4s 2 3d 2 4s 2 3d 3 4s 3d 5 4s 2 3d 5 4s 2 3d Rb Sr Y Zr Nb Mo Tc Ru 5s 5s 2 5s 2 4d 2 5s 2 4d 2 5s 2 4d 3 5s 4d 5 5s 2 3d 5 5s 4d Cs Ba La* f Ta W Re Os 6s 6s 2 6s 2 5d 6s 2 5d 2 6s 2 5d 3 6s 2 5d 4 6s 2 4d 5 6s 2 5d 6 87 Fr 7s 88 Ra 7s 2 89 Ac # 7s 2 6d s 2 6d s 2 7d s 2 6d s 2 3d s 2 6d 6 27 Co 4s 2 3d 7 45 Rh 5s 4d 8 77 Ir 5d 7 6s d 7 7s 2 28 Ni 4s 2 3d 8 46 Pd 4d 0 78 Pt 6s 5d 9 29 Cu 4s 3d 0 47 Ag 5s 4d 0 79 Au 6s 5d Al 3s IIB 2 3p 30 Zn 4s 2 3d 0 48 Cd 5s 2 4d 0 80 g 6s 2 5d 0 3 Ga 4s 2 4p 49 In 5s 2 5p 8 Tl 6s 2 6p + Element synthesized, but no official name assigned 32 Ge 4s 2 4p 2 50 Sn 5s 2 5p s 2 6p 2 5 Sb 5s 2 5p 3 83 Bi 6s 2 6p 3 84 Po 6s 2 6p 4 Multiple oxidation state metal ions Some metal ions can act as an oxidizing or reducing agent! Example: Sn = 0, 2 + and 4 + Sn 2+ ion can gain electrons = OA: Sn e- Sn Sn 2+ ion can lose electrons = RA: Sn 2+ Sn e- Predic'ng Redox Strength Electronega'vity and Redox Strength

7 Electronegativity and Redox Strength Electronegativity values (p.222, manual) reflect an elements attraction for electrons when forming a bond IA IIA IIIB IVB VB VIB VIIB VIIIB IB IIB IIIA IVA VA VIA VIIA 2. Li Be B C N O F Al Si P S Cl K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Cs Ba La f Ta W Re Os Lu Fr Ra Ac Th Pa U Np- N o Ir 2.2 Pt 2.2 Au 2.4 g.9 Tl.8.8 Bi.9 Po 2.0 At 2.2 IA IIA IIIB IVB VB VIB VIIB VIIIB IB IIB IIIA IVA VA VIA VIIA 2. Li.0 Q. Where are the best oxidizing agents located in the electronegativity table? Be K Ca Sc Ti V Cr Mn Fe Co Rb Sr Y Zr Nb Mo Tc Ru Rh Cs Ba La f Ta W Re Os Ir Lu Fr Ra Ac Th Pa U Np- N o B 2.0 C 2.5 N 3.0 O 3.5 F 4.0 Al Si P S Cl Ni Cu Zn Ga Ge As Se Br Pd Ag Cd In Sn Sb Te I Pt Au g Tl Bi Po At IA IIA IIIB IVB VB VIB VIIB VIIIB IB IIB IIIA IVA VA VIA VIIA 2. Li.0 Q. Where are the best reducing agents located in the electronegativity table? Be K Ca Sc Ti V Cr Mn Fe Co Rb Sr Y Zr Nb Mo Tc Ru Rh Cs Ba La f Ta W Re Os Ir Lu Fr Ra Ac Th Pa U Np- N o B 2.0 C 2.5 N 3.0 O 3.5 F 4.0 Al Si P S Cl Ni Cu Zn Ga Ge As Se Br Pd Ag Cd In Sn Sb Te I Pt Au g Tl Bi Po At

8 Part IA. Metal reactions with water Rank the reducing agent strength of the metals Na, K, Mg, and Ca from experimental observations. Correlate reactivity results with the position of the metal in the periodic table. IA IIA IIIB IVB VB VIB VIIB VIIIB IB IIB IIIA IVA VA VIA VIIA 2. Li.0 Q. Predict the RA strength of Mg and Ca based on position and electronegativity values. Be K Ca Sc Ti V Cr Mn Fe Co Rb Sr Y Zr Nb Mo Tc Ru Rh Cs Ba La f Ta W Re Os Ir Lu Fr Ra Ac Th Pa U Np- N o B C N O F Al Si P S Cl Ni Cu Zn Ga Ge As Se Br Pd Ag Cd In Sn Sb Te I Pt Au g Tl Bi Po At > Experimental Comparison of Ca and Mg Metal + Water metal hydroxide + 2 (g) RA OA OA RA Example: Mg(s) + 2O(l) Mg(O) 2 (s) + 2 (g) DEMO RA: >

9 Q. Predict the RA strength of K and Na compared to Mg and Ca based on electronegativity values. IA IIA IIIB IVB VB VIB VIIB VIIIB IB IIB IIIA IVA VA VIA VIIA 2. Li.0 Be K Ca Sc Ti V Cr Mn Fe Co Rb Sr Y Zr Nb Mo Tc Ru Rh Cs Ba La f Ta W Re Os Ir Lu Fr Ra Ac Th Pa U Np- N o B C N O F Al Si P S Cl Ni Cu Zn Ga Ge As Se Br Pd Ag Cd In Sn Sb Te I Pt Au g Tl Bi Po At > > > Reactivity of K and Na Experimental determination of the reactivity of K and Na compared to Ca and Mg. Part I B. Predicting Metal Reactivity. Experimentally determine the reducing agent (RA) strength of four team assigned metals Information: Only three of the four metals will be provided Four of the assigned metal s ions will be provided

10 Part B Experiment Design Example You need to determine the reducing agent strength of, Cu, and Ag. Information: Solutions of metal ions 2+, Cu 2+, Ag + in the form of 0.0 M metal ion nitrate salts Cu and Ag only (i.e., is unavailable) Table Design for Part B. ) Create a table for recording data (pre-lab). Ag Cu Ag + Cu Reducing agents (metals) on one side and oxidizing agents (metal ions) on other side. Part B experiment 2) Combine different available metals and metal ions (0.0 M metal ion nitrates) Ag + Cu Ag NO Cu NO NO Example: Cu + Ag + versus Ag + Cu 2+

11 Ag(s) + Cu 2+ (aq) versus Cu(s) + Ag + (aq) Q. Based on experiment results, rank: -The oxidizing agents (Ag + and Cu 2+ ) - The reducing agents (Ag and Cu) OA: > RA: > Cu(s) + Ag + (aq) YES Ag(s) + Cu 2+ (aq) NO Metal and Metal Ion Reactions RA: Cu > Ag OA: Ag + > Cu 2+ Stronger RA and OA = Reactants Cu(s) + 2 Ag + (aq) 2 Ag(s) + Cu 2+ (aq)

12 Part B experiment 4) Enter all tested results for available metal and metal ion combos into Part B Table Ag + Cu Ag NO NO NO Cu YES NO NO NO 5) Complete the table and indicate the comparative RA strength of Ag, Cu, and. Ag + Cu Ag NO NO NO Cu YES NO NO NO 0 RA strength: Questions? Contact nkerner@umich.edu