Chemistry Questions (Coursework Sample)

SECTION 1- NUMERICAL: REACTION CALCULATIONS SECTION 2 - THEORETICAL: 1,2 – ALKYL MIGRATION WITH DOUBLE INVERSION OF CONFIGURATION: MECHANISTIC INSIGHTS Name : Course: Tutor: University: Location: Date: Table of Contents a. Title Page…………………………………………….………………1 b. Table of Contents……………………………………………………2 c. Section 1- Numerical………………………………………………..3 d. Section 2 - Theoretical………………………………………………5 d. Introduction…………………………………………………………..5 e. Mechanism…………………………………………………...………5 f. Uses of the Compound Obtained…………………………….……….6 g. References……………………………………………………………7 Section 1-Numerical Step 1: Balanced Equation The balanced equation between potassium permanganate and iron(II) is: MnO4(aq)−+8H+(aq)+Fe2+(aq)→Mn2+(aq)+5Fe3+(aq)+4H2O(l) So, u = 1, v = 8, w = 5, x = 1, y = 5, and z = 4. Step 2: Calculate the Molarity of Iron(II) Given: Volume of potassium permanganate = 24.3 cm3 Molarity of potassium permanganate = 0.02 mol/dm3 Volume of iron(II) solution = 20 cm3 Using the balanced equation: 5 moles of Fe2+ react with 1 mole of MnO4− Number of moles of MnO4− reacted: Moles of MnO4− = 0.02 mol/dm3 × 0.0243 dm3 = 0.000486 moles Number of moles of Fe2+ reacted: Moles of Fe2+ = 0.000486 moles / 5 = 9.72 x 10−5 moles Volume of iron(II) solution in dm3: Volume = 20 cm3 = 0.02 dm3 Molarity of iron(II), k: k = 9.72x 10−5 moles / 0.02 dm3 = 0.00486 mol/dm3 Step 3: Percentage of Iron in Steel Wire Given: Weight of steel wire = 1.75 g Molar mass of Fe = 56 g/mol Number of moles of Fe in steel wire: Moles of Fe = 1.75 g / 56 g/mol = 0.03125 moles Percentage of Fe in steel wire, m: m = (0.03125 moles / 1.75 g) x 100 = 1.7857% Step 4: Calculate the Molarity of Iron(II) from Iron(II) Salt Given: Volume of iron(II) solution = 25 cm3 Titration values: Reading 1: 23.95cm3 Reading 2: 23.8 cm3 Reading 3: 25.85 cm3 Average titration value: Average = (23.95 cm3 + 23.8 cm3 + 25.85 cm3) / 3 = 24.2 cm3 Number of moles of MnO4− used: Moles = 0.02 mol/dm3 × 0.0242 dm3 = 0.000484 moles Number of moles of Fe2+ reacted: Moles of Fe2+ = 0.000484 moles / 5 = 9.68 x 10−5 moles Volume of iron(II) solution in dm3: Volume = 25 cm3 = 0.025 dm3 Molarity of iron(II) from iron(II) salt: k' = 9.68 x x 10−5 moles / 0.025 dm3 = 0.003872 mol/dm3 Step 5: Evaluate the Expression Expression = 100m - 1000(a - b - k) - (u + v + w + x + y + z) Substitute the calculated values: Expression = 100(1.7857) - 1000(1 - 0.017857 - 0.00486) - (1 + 8 + 5 + 1 + 5 + 4) Calculate: Expression = 178.57 - 1000(0.977283) - 24 Expression = 178.57 - 977.283 - 24 Expression = -822.713 So, the value of the expression is -822.713. Section 2- Theoretical Introduction The transformation of complex organic molecules often involves intricate rearrangements of the carbon skeleton to access new functionalities or structures. One such fascinating reaction is the 1,2-alkyl migration with double inversion of configuration, which results in the formation of a new compound with a rearranged carbon framework(Liu et al. 2016). This rearrangement typically starts from a molecule containing a diazo group, a functional group with a nitrogen-nitrogen double bond. The reaction proceeds through the formation of a diazonium intermediate and culminates in the migration of an alkyl group, accompanied by the expulsion of nitrogen gas(Yamazaki et al. 2021). This reaction is not only synthetically valuable but also crucial for the development of various organic compounds with potential applications in pharmaceuticals and materials science. Mechanism The mechanism of 1,2-alkyl migration with double inversion of configuration involves several key steps: Formation of Diazonium Intermediate: The reaction begins with the conversion of the diazo group into a diazonium ion, facilitated by the presence of a suitable reagent or catalyst. Nucleophilic Attack: A nucleophile, often a carbon-based species within the molecule, attacks the diazonium ion. This step leads to the migration of the alkyl group from one carbon to an adjacent carbon atom(Empel et al. 2023). Loss of Nitrogen Gas: Concurrently, nitrogen gas (N2) is expelled from the diazonium ion, stabilizing the newly formed intermediate. Double Inversion: Remarkably, the mi...