Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
CH 103: THE SYNTHESIS OF A COMPOUND USING A LIMITING REAGENT NiCl26H2O(aq) + 3H2NCH2CH2NH2(aq) [Ni(H2NCH2CH2NH2)3]Cl2(s) + 6H2O(l) • Stoichiometry is the numerical relationship between the moles of reactants and the moles of products for a chemical reaction. • What is the mole ratio of ethylenediamine (en, H2NCH2CH2NH2) to nickel(II) chloride hexahydrate (NiCl26H2O)? • The limiting reagent is the reactant that is completely consumed during a chemical reaction. Therefore, the yield or amount of product formed depends on the amount of limiting reagent. • What is the limiting reagent if the actual mole ratio of H2NCH2CH2NH2 / NiCl26H2O is 1/1? • H2NCH2CH2NH2 • What is the limiting reagent if the actual mole ratio of H2NCH2CH2NH2 / NiCl26H2O is 5/1? • NiCl26H2O LEWIS ACIDS AND LEWIS BASES • • • • • Gilbert Lewis A Lewis acid is an electron-pair acceptor. A Lewis base is an electron-pair donor. Which reactant is a Lewis acid? Ni2+ Which reactant is a Lewis base? COMPLEX IONS, LIGANDS, AND COORDINATION NUMBERS • A complex ion is an ion that has a central metal cation bonded (or coordinated) to 1 or more groups of atoms. These groups of atoms are called ligands. • Coordination number is the number of ligand atoms that bond to the central metal of a complex ion. • What is the metal atom in this complex ion? • Ni2+ • What is the ligand? • In fact, H2NCH2CH2NH2 is a bidentate ligand. Each H2NCH2CH2NH2 has 2 different atoms that bond to the central Ni2+. • What is the coordination number for this complex ion? • 6 COMPLEX IONS, LIGANDS, AND COORDINATION NUMBERS • Name the ligand and coordination number for each of these 3 complex ions. Ligand = Chloride, ClCoordination # = 2 Ligand = Ammonia, NH3 Coordination # = 4 • Are any of these ligands bidentate? • No Ligand = Water, H2O Coordination # = 6 THE SYNTHESIS OF A COMPOUND USING A LIMITING REAGENT • The purpose of this experiment is to identify the limiting reagent for the following reaction: NiCl26H2O(aq) + 3H2NCH2CH2NH2(aq) [Ni(H2NCH2CH2NH2)3]Cl2(s) + 6H2O(l) • How will you do this? • Simply compare your experimental mole ratio of H2NCH2CH2NH2 / NiCl26H2O with the theoretical mole ratio of 3/1 for this reaction. If it is less than 3/1 then H2NCH2CH2NH2 is the limiting reagent. If it is greater than NiCl26H2O is the liming reagent. 3/1 then • Once the limiting reagent is known, you can calculate the theoretical yield of product ([Ni(H2NCH2CH2NH2)3]Cl2) and the percent yield of product. SAFETY • Give at least 1 safety concern for the following procedures that will be used in today’s experiment. • Using NiCl26H2O, H2NCH2CH2NH2), and acetone (CH3COCH3). • These are irritants. Wear your goggles at all times. Immediately clean all spills. If you do get either of these in your eye, immediately flush with water. • Acetone is extremely flammable. Never use it near a flame or spark. • Your laboratory manual has an extensive list of safety procedures. Read and understand this section. • Ask your instructor if you ever have any questions about safety. SOURCES • McMurry, J., R.C. Fay. 2004. Chemistry, 4th ed. Upper Saddle River, NJ: Prentice Hall. • Park, J.L. 2004. ChemTeam: Photo Gallery Menu. Available: http://dbhs.wvusd.k12.ca.us/webdocs/Gallery/GalleryMenu. html [accessed 30 October 2006]. • Petrucci, R.H. 1985. General Chemistry Principles and Modern Applications, 4th ed. New York, NY: Macmillan Publishing Company.