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University Degree: Chemistry

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  1. Synthesis and Characterization by UV-Vis Spectroscopy, EPR, and HNMR of H2TPP and CuTPP Porphyrins

    An often used porphyrin derivative, meso-tetra-phenyl porphyrin (TPP), was the porphyrin derivative used in this experiment. Due to its relative stability, relative ease of synthesis, and high degree of characterization, H2TPP, shown in Figure 1, and CuTPP, shown in Figure 1, were ideal choices for the present investigation. Figure 1: Figure 2: Tetra-phenyl porphyrin Copper(II) tetra-phenyl porphyrin To effectively characterize Cu(II)TPP, a method to separate the subject compound from unreacted H2TPP was necessary. To that end, the technique of thin layer chromatography (TLC)

    • Word count: 3101
  2. Lewis Acid and Bases, Spartan Molecular Modeling, and Isotopic Labeling. One objective of this lab was to understand what Lewis acids and Lewis bases are and how they can react with each other. Additionally, modeling program Spartan was used to understand

    The adduct above can be referred to as the 1H adduct because the boron is protonated with hydrogens of atomic mass 1 amu. However, the H1can be replaced in this reaction by the isotope deuterium, 2H (atomic mass 2 amu), in which case the reactant BH4Na is denoted as BD4Na and the product formed is D3B-NH2(C(CH3)3). Deuterium has physical and chemical properties that are very similar to 1H, so it can be easily substituted in a reaction.1 It also serves as a tracer, meaning that 2H can be followed in multiple reactions through the use of IR spectroscopy.

    • Word count: 1500
  3. The preparation of alum from scrap aluminium. In this experiment, instead of recycling aluminium into new metal cans, a chemical process will be used that transforms scrap aluminium into a useful chemical compound, potassium aluminium sulfate dodecahydrat

    Production of aluminium from raw materials is an energy intensive process" (The Preparation of Common Alum from Scrap Aluminium, 2002). In this experiment, instead of recycling aluminium into new metal cans, a chemical process will be used that transforms scrap aluminium into a useful chemical compound, potassium aluminium sulfate dodecahydrate, KAl(S04)2�12 H2O, commonly called "alum" and will also produce hydrogen gas. Hydrogen gas has great potential use as a fuel, if some of its dangerous properties can be controlled (mixtures of H2 and air are highly explosive).

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  4. Trends in the periodic table. This experiment, through calculating the density of four samples and determining the solubility of the alkaline earth metal salts, investigated periodic trends in density and solubility.

    Introduction The aim of this experiment was to investigate trends in the periodic table of density and solubility. The aim of the density experiment was to see if the density of an element could be determined through interpolation by drawing a graph of the density against period number for the four samples measured in the experiment. The hypothesis of bigger molecules are less soluble in solutions was tested in the solubility experiment considering the lattice enthalpy and hydration enthalpy factors.

    • Word count: 1493
  5. Free essay

    The preparation and analysis of potassium nitrilosulfonate, N(SO3K)3.2H2O

    Introduction The aim for the first part of the experiment was to synthesise potassium nitrilosulfonate. The sulfonic acid derivatives can all be prepared from the reaction between NH3 and SO3 but in this experiment another method was followed to prepare nitrilosulfonate (figure 1& Inorganic Chemistry 244 Practical Manual, 2011:8). The K2S2O5 is prepared in situ from the hydrolysis of potassium metabisulfate. It is significant to know that no information concerning the rate of hydrolysis and stability of the primary reaction product, the nitrilosulfonate, or of the intermediate, imidodisulfonate, has been recorded thus far. The synthesis of potassium nitrilosulfonate must be done in carefully controlled conditions for the experiment to be a success (Sisler & Audrieth, 1938:1947).

    • Word count: 1288
  6. Heat Capacity Ratio for Gases. The experimental heat capacity ratio of N2 gas is computed as 1.28 (0.02) with the help of the adiabatic expansion method. This value is closer to the theoretical value of 1.29 when vibrational contribution to Čv is

    CV (J mol-1 K-1) Without vibrational With vibrational Without vibrational With vibrational 29.099 37.413 20.785 29.099 Table 5: Heat Capacity Ratio of N2 (Experimental and Theoretical) Experimental Heat Capacity Ratio Theoretical Heat Capacity Ratio Error (%) Without vibrational With vibrational Without vibrational With vibrational 1.28 � 0.02 1.40 1.29 8.88 0.78 VI. Results and Discussion: Heat capacity is the amount of heat required to raise the temperature of a system by 1 oC or 1 K. Moreover, it is affected by the movement of the molecules with a corresponding kinetic energy that is produced upon its motion which can be translational, rotational and vibrational (for gas molecules).

    • Word count: 1865
  7. Spectrochemical Series of Some d-block Transition Metal Complexes. The spectrochemical series of the ligands for Cu(II), Co(II) and Cu(II) ions were constructed by visual inspection and spectral analysis of the transition metal complexes. Results show tha

    Valence Bond Theory prognosticates the magnetic properties and structures of the complexes but it fails to account for the color of the coordination compounds formed by transition metals. Rather, the Crystal Field Theory (CFT) is often used to discuss the splitting in the d orbitals' energies. The degeneracy that occurs among the five d orbitals of free metal atoms and ions ceases once the metal binds to a ligand. CFT focuses on the electrostatic interactions within the complex but ignores covalent bonding.

    • Word count: 1981
  8. EDTA Titration

    Initially, the dye was wine red with a pH of 9.3. When the EDTA was added, a color change was observed. The color change indicated that all the dye had been displaced from the metal cations in the solution and had formed a chelate. A chelate is the complex formed through the process of reversible bonding of a ligand to a metal ion. In this experiment, the ligand was EDTA (ethylenediamine tetraacetic acid). These complexes are stable in a buffer solution.

    • Word count: 1302
  9. Determination of Concentration of Strong Acid/Strong Base by Titration

    A description of concentration in terms of amount of solute is molarity, where the moles of solute is compared to liters of solvent. In this experiment, the acid used was hydrochloric acid, HCl, and the base was sodium hydroxide, NaOH. Two different equations were used in determining molar concentration, or molarity. The first reaction appears as follows: For NaOH, since the molar ratio was 1:1, the following equation was used: Molarity of HCl was determined using the values from the first experiment and another titration in this equation, the dilution equation, which can be used for titration if there is a 1:1 mole ratio: or (MNaOH)(VNaOH)

    • Word count: 1292
  10. Preparation of Solutions

    Data collected before the reaction included the molar mass of copper sulfate pentahydrate (CuSO4 ? 5H2O) found by the use of the values on the periodic table and the mass of copper sulfate pentahydrate (CuSO4 ? 5H2O) needed to prepare ten milliliters of a 0.140 M solution. Copper sulfate pentahydrate (CuSO4 ? 5H2O) is a light blue crystalline solid substance. The chemical reactions that took place involved hydration of copper sulfate pentahydrate (CuSO4 ? 5H2O) in deionized water and dilution of a stock solution.

    • Word count: 920
  11. Experiment 12: The Paramagnetic Complex- Mn(acac)3

    This experiment involves the preparation of a Mn(III) complex of acetyl acetone, which is Tris(acetylacetonato)manganese(III). The high or low spin of the complex was determined by using magnetic susceptibility. Experimental Details: First and foremost, the safety precautions should be noted. Potassium permanganate is a strong oxidant. If the chemical is spilled on the skin, immediately wash off with water. All glassware must be cleaned properly. The first step is to make the Tris(acetylacetonato)manganese(III). In a 250 mL beaker, 3.75 grams of potassium permanganate was measured.

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  12. The Synthesis and Optical Resolution of Co(en)33+ isomers

    Second-order Asymmetric Induction is when one of the enantiomers can react with a chiral ion. This changes the solubility properties of the one enantiomer making it more soluble then the other. The other enantiomer then crystallizes out first, making it easy to filter one from the other.(2,3) The [(+)-Co(en)3[(+)-tart]Cl is first synthesized and then is converted to [(+)Co(en)3]I3 H2O by reaction with NaI. The other optical isomer, [(-)Co(en)3]I3, is obtained by adding NaI to the filtrate from which [(+)-Co(en)3][(+)-tart]CI 5H2O was previously precipitated.

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  13. Synthesis of Benzocaine

    Thus the theoretical yield of benzocaine is expected to be 0.036 mols as a 1:1 ratio exists between and 4-aminobenzoic acid and benzocaine. % yield = = = 69 % (2 S.F.) D. Procedure: No changes were made to the procedure given in CHEM3061 Laboratory Manual, p. 1-1 to 1-2. E. Results: Addition of concentrated sulfuric acid to the p-aminobenzoic acid, ethanol mix generated a white solid precipitate to form. Addition of 10% sodium carbonate solution to the refluxed solution above caused effervescing to occur.

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  14. Determination of the Enthalpy (Heat) of Reaction of a Monobasic Acid with Sodium Hydroxide

    The water in the flask was stirred slowly and regularly with a thermometer. 3. The temperature of the water was recorded at intervals of 1 minute over a period of 5 minutes. 4. About 2 cm� of concentrated sulphuric acid was introduced into the calorimeter by a graduated cylinder at the end of the period. 5. The solution in the calorimeter was continually stirred; the temperature was continually measured and recorded at 1 minute interval over the period of 10 minutesuntil the temperature value had become constant.

    • Word count: 1912
  15. Hydrolysis of Salts and choice of Indicators / Titration Curve

    Thus, according to the Bronsted-Lowry concept, an acid is a proton-donor, and a base is a proton-acceptor. The reaction of an acid with a base involves transfer of a proton from the acid to the base. So, an acid and a base should be present simultaneously in any system. The extent of an acid-base reaction is governed not only by the proton-donating ability of the acid, but also by the proton-accepting tendency of the base. Acids and bases classified on the basis of this concept are termed as Bronsted acids and bases.

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  16. Synthesis of Aspirin by Green Chemistry Methods

    In classical synthesis, salicylic acid and acetic anhydride are refluxed with a strong acid in benzene. Although this method yields the desired product, it is not clean. Just as engineering requires optimization, so too does chemistry. In this experiment, no solvent is used to form aspirin. The reactants are mixed together and heated via two different methods to yield the desired compound. On one hand, conventional heating is used while microwave oven heating is employed on the other hand. In both cases, after quenching the reaction with water, only aspirin and acetic acid remain along with the salicylic acid that has not reacted.

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  17. Chemical Equilibrium

    color change ----- 4 NaOH Orange-Yellow Cr2O72- + 2OH- - C 2CrO42- + H2O Reactions for the chromate-dichromate system: [1] 2CrO42- + 2H+ - Cr2O72- + H2O; (Yellow) (Orange) [2] 2CrO42- + 2H+ --> Cr2O72- + H2O; (Yellow) (Orange) [3] Cr2O72- + 2OH- --> 2CrO42- + H2O (Orange) (Yellow) Equation 1 is the equilibrium reaction. From this equation, we can derive the Keq. Keq = [Cr2O72-] / [H+]2 [CrO42-]2 The Le Ch�telier's principle predicts that the forward reaction, which is essentially equation 2, is favored in acidic medium and there will be predominantly Cr2O72- thus giving the solution an orange color when H2SO4 was added.

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  18. Spectrophotometric Determination of the Equilibrium Constant of a Reaction

    A spectrophotometer is a light measuring device that measures intensity as a function of the light source wavelength. The amount of light that had passed through the system is called the transmittance. The amount of light absorbed by the system is called the absorbance. However, the absorbance of [Fe(SCN)]2+ is the one that the experiment is concerned with. The concept of the Q, the reaction quotient is needed. There are infinitely many Q's for a given reaction. The reaction quotient at state where the rate of the forward reaction and the reverse reaction are equal is called the Keq.

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  19. Coupled Reactions

    This means that the reactions released heat and are therefore, exothermic. On the other hand, the precipitation reaction yielded a negative change in temperature which pertains to a reaction that absorbs heat and therefore, endothermic. The calculated percent errors were abnormally large. The possible sources of errors can be: first, the lid/cork was not replaced immediately after pouring/putting the 2nd reagent in to the test tube. Second, there were some errors on the preparation of the solutions. Third, the temperature readings were taken immediately after a reagent was poured in to the test tube instead of waiting for the temperature

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  20. Identifying unknown sample using test of functional group and IR/UV spectra.

    Moreover, there is another simple test for solubility, heating on nickel foil and damping litmus paper. This test for preliminary information regarding for sample drug (81) which is related to functional group tests. For instance, if the compound does not dissolve in water and it dissolve in NaOH, then the compound is significantly more soluble in strong base, which means it is phenol. Structure Before lab it is necessary to have looked up the structure of each compound, so that it can be easy to predict which compound is sample drug 81 when testing different functional groups that give a positive or negative result.

    • Word count: 1645
  21. Synthesis and Characterization of [Co(NH3)4CO3]NO3

    Hydrogen peroxide is used as the oxidizing agent, so it is reduced to water. The formation of the coordination compound is a redox reaction, and the equation can be balanced using half-equations. The balanced equation is shown below: 2Co(NO3)2 + 6NH3 + 2(NH4)2CO3 + H2O2 --> 2[Co(NH3)4CO3]NO3 + 2NH4NO3 + 2H2O Theoretically, carbonatotetraamminecobalt (III) nitrate is formed, but further analysis of the coordination compound will be necessary to validate this assertion. The complex will be characterized in terms of absorbance, conductivity, magnetic susceptibility, and infrared spectroscopy.

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  22. Synthesis of [Co(NH3)5Cl]Cl2:

    Kinetics is the study of motion. In the study of kinetics of the compound being prepared, the H+ ion movement can be determined 3. Having a model of this reaction can be useful in predicting reaction kinetics for similar reactions. Experimental (Experiment 1 Handout, PLU Department of Chemistry) In this experiment, pure ethanol was used. Also the HCl and NH3 was a concentrate. First, 5.0 grams of [Co(NH3)4CO3]NO3 was dissolved in 50 mL of H2O in a beaker. When the 5 to 10 mL of HCl was added to the previous solution, the CO2 was expelled and HCl was added until all of the CO2 was expelled.

    • Word count: 1132
  23. Synthesis of chloropentaaminecobalt(lll) chloride

    The synthesis of cobalt(lll) complexes involved oxidation of the cobalt(lll) salt in the presence of the desired ligands. Carbonato compounds made intermediates in the synthesis of cobalt complexes in which carbonate ion was removed by HCl which expelled the carbonate.1 The complex was characterized in terms of conductivity and infrared spectroscopy. Measuring the conductivity of the cobalt coordination compound was necessary to determine how many ions were present in one formula unit of the complex. The expected conclusion was three ions, resulting in a conductance of 235-273. An infrared spectrum is a plot of the absorption intensities of different wavelengths of infrared light.2 The IR spectrum of [Co(NH3)5Cl]Cl2 consists of absorptions primarily attributed to the NH3 groups.

    • Word count: 1450
  24. Preparation of alum from scrap aluminium

    of: Important types of alum and their respected formulas 1. Potash alum - KAl(SO4)2�12H2O 2. Soda alum - NaCr(SO4)2�12H2O 3. Chrome alum - KCr(SO4)2�12H2O Potash alum is used in papermaking, fire extinguishers, and food stuffs and in the purification of water. Soda alum is used in baking powders. Chrome alum is used in tanning leather and water proofing fabrics.2 & 3 The aim of this experiment was firstly to convert a piece aluminium metal into a chemical compound known as potassium aluminium sulphate dodecahydrate, KAl(SO4)2�12H2O, or commonly referred to as alum.

    • Word count: 1517
  25. Ion exchange

    Amphoteric exchangers exchange both cations and anions simultaneously.2 An ion-exchange resin (refer to figure 1) is an insoluble matrix normally in the form of small beads, yellowish in colour, fabricated from an organic polymer substrate. They are capable of exchanging particular ions within the polymer with ions in a solution that is passed through them. Synthetic resins are used in various applications including separating out some elements.3 Most typical ion-exchange resins are based on cross linked polystyrene.1 The aim of this experiment was to separate a mixture of Fe3+ and Ni2+ using the anion exchange resin, Amberlite IRA-400. We then had to determine the Ni2+ and Fe3+ content of the two solutions from experiment 2a.

    • Word count: 959

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