General Chemistry II, PAL Worksheet – Week 11 (Wed/Th)

PAL – Week 11 (Wed/Th) #18  EChem Part 4/Transition Metals (Ch 24)       Name:   Part A: Cell Potential and Concentration True or False _____ A concentration cell is an electrochemical cell that is comprised of two half-cells with the same electrodes, but differing in concentrations. _____ In a concentration cell, electrons move from the higher concentration cell to the lower concentration cell. _____ A pH meter is a specific type of concentration cell that uses the basic setup of a concentration cell to determine the pH, or the acidity/basicity, of a specific solution. 1. For the concentration cell bellow determine which compartment contains the anode and which contains the cathode. Then determine the flow of electrons. Compartment 1 Compartment 2 2+ 2+ Fe|Fe (aq,0.01M)||Fe (aq, 0.1M)|Fe 2. Calculate cell potential, Ecell, for the concentration cell listed above. Use the Nernst equation listed below. Do you know the value for E o cell? 3. Calculate the concentration of the unknown, given the equation below and a cell potential, Ecell = 0.26V. Ag|Ag+(xM)||Ag+(1.0M)|Ag   1                                                       Part B: Properties of Transition Metals True and False _______As we move across the periodic table from left to right, the radii for transition metals decreases then increases slightly. Why?_________________________________________________________________________ _____________________________________________________________________________ _______As we move down a group (from row 1 to 2), the radii for transition metals increases. Why?_________________________________________________________________________ _____________________________________________________________________________ _______As we move across the periodic table from left to right, ionization energy increases. The Ionization energy of Zn is much much greater than Cr. Why?________________________ _____________________________________________________________________________ 4. What is the oxidation state of the metal in the oxides listed below? a) ScCl2 b) TiO c) V2O5 d) Cr2O3 e) MnF2 f) KMnO4 For compounds a-f, write the electron configuration for the transition metals. 5. As you can see from your answer in 4, there are many possible oxidation states for transition metals. What is a common oxidation state for transition metal ions? Why?   2                                                     Part C: Complex ions or Coordination Complexes Coordination Complexes are Complex ions. They consist of a transition metal and one or more small molecules (known as Ligands) that are attached. The bonding interaction between the transition metal and the ligand is a Lewis Acid-Base interaction. Fill out the following missing blanks in the table. Example Chemical Formula Lewis Acid Lewis Base Coordination number [Ag(NH3)2]+ [PtCl6]2- [Fe(H2O)4Cl2]   3                                                     In Exp 14, you will synthesize one of the following cobalt compounds. From the formulas, practice drawing the structures. 1) [Co(NH3)5Cl]Cl2         2)  [Co(NH3)5(H2O)]Cl3 3) [Co(NH3)5(ONO)]Cl2     4) [Co(NH3)5(NO2)]Cl2     5) [Co(NH3)6]Cl3       4