Final Exam b Chem 121-Prody December 12, 2007 Name___________Show ALL your work. Use the correct number of significant digits. No credit will be given for answers alone.1. (15 points) How much energy would be required to ionize 5.00 x1027 Li atoms to Li+ atoms? The first ionization energy of Li atoms is 520 kJ/mol.5.00 x 10 27 Li atoms (1 mole Li atoms/6.02 x1023 Li atoms) (520 kJ/mol Li atoms) =2. (30 points) Dicyandiamide, N4C2H4, is used in the manufacture of plastics. Draw a plausible Lewis structure for this molecule. Indicate a hybridization scheme for the central atom of this structure, and indicate approximate bond angles you would expect to find in the molecule. For extra credit, also draw an isomer of this structure.H-N=N-CH=CH-N=N-H or H2N-N=C=C=N-NH2 or N≡C-NH=C(C=NH)-NH2 or othersC sp2 C sp120 1803. (14 points) A stock solution of potassium dichromate is made by dissolving 39.8 g of the compound in 1.00 L of solution. How many milliliters of this solution are required to prepare 1.50 L of 0.100 M potassium dichromate?39.8 g K2Cr2O7 (mol K2Cr2O7/294.2 g K2Cr2O7)/ (1.0 L) = 0.135 M0.135 M v = 0.100 M (1.5 L) v = 1.11 L4. (35) A metal, M was converted to the chloride, MCl2, in a final reaction volume of 250 mL. Then this solution of the chloride was treated with silver nitrate to give silver chloride crystals which were filtered off. All other participants are soluble.a. Write a balanced equation for the reaction of the metal chloride with silver nitrate.2 AgNO3 + MCl2 → 2 AgCl + M(NO3)2b. If 2.434 g of the metal gave 7.964 g of silver chloride, what is the atomic weight of the metal? What is the metal?7.964 g AgCl (1 mol AgCl/143.32 g AgCl) ( 1 mol M/2 mol AgCl) = 0.02779 mol MAW = 2.434 g M/0.02779 mol M = 87.59 g/mol = Src. What was the molarity of the metal chloride in the first reaction?0.02779 mol MCl2/0.250 L = 0.111 M5. (12 points) The nucleus of a radon atom, 222Rn, contains:____136 _______n +____86______pHow many neutrons are present in 6.00 g Rn?6.0 g Rn ( 1 mol Rn/222 g Rn)(6.02 x 1023 atoms Rn/mol Rn)(136 n/molRn) = 2.21 x 1024 n6. (12 points) Name the following:a) Ag2CO3__silver carbonate__________ b) NH4F________ammonium fluoride________c) FeSO3 ___Iron (II) sulfite__________ d) Be(OH)2__Beryllium hydroxide_______7. (12 points) Write the formulas for:a) Nickel (III) phosphide ____NiP__________ b)Aluminum sulfate _____Al2(SO4)3_________c) Magnesium acetate __Mg(C2H3O2)2_________ d) Barium perchlorate __Ba(ClO4)2__________8. (12 points) Draw Lewis structures for 2 stereoisomers and one structural isomer of C2H2Cl2. Labelthem appropriately and indicate polarity, if present.See figure 10.28 + one with both Cl on one C9. (4 points) What is electronegativity? Which element is most electronegative? ____F____Ability to attract electrons10. (20 points) An ionic compound has the following composition by mass: Ca, 30.3%; N, 21.2%;, O,48.5%. What are the formula and name of the compound? Write the Lewis structures for the ions. 30.3 g Ca (1 mol Ca/40.08 g Ca) =0.76 mol Ca21.2 g N (1 mol N/14.01 g N) = 1.51 mol N48.5 g O (1 mol O/16.00 g O) = 3.03 mol O Ca (NO2)2calcium nitrite12. (10 points) Write balanced net ionic equations for the following reactions. If no reaction occurs, write NR. Note: all sulfides and phosphates are insoluble, except group IA.a) aluminum nitrite + cesium sulfide2 Al+3(aq) + 3 S-2(aq) → Al2S3 (s)b) lithium phosphate + calcium iodide3 Ca+2(aq) + 2 PO4-3(aq) → Ca3(PO4)2 (s)13. (18 points) Draw Lewis a structure for each of the following. Indicate bond angles, bond hybridizations and polarity, if any.a) CH3NH2b) C2H4O c) CO2H3C-NH2H3C-CH=O O=C=Osp3sp3 sp2sp109 109 120 18014. (4 points) Describe a 