Exams & Certification

Diborane (B2H6, molar mass 27.69 g/mol) can be made from sodium borohydride (NaBH, molar mass 37.85 g/mol) by reacting it with iodine in the following reaction: 2NaBH4 (s)+12 B2He (g)+ 2 Nal (s)+ H2 (9) If 1.203 g NaBH4 is combined with excess l2 and 0.295 g B2Hs is isolated, what is the percent yield […]

Write the symbol for alpha, beta, and gamma radiation. Include the atomic mass and atomic number, where relevant. The Correct Answer and Explanation is : Symbols for Alpha, Beta, and Gamma Radiation: These different types of radiation are significant in fields like nuclear physics and medical imaging, where proper understanding and shielding are essential for

Compare the IR spectrum of benzil with meso-hydrobenzoin. Considering carbonyl, OH, aromatic CH, and aliphatic CH absorption bands, describe the similarities and differences you find. meso-hydrobenzoin (final product): The Correct Answer and Explanation is : 1. Carbonyl Group (C=O) Stretching 2. Hydroxyl Group (O-H) Stretching 3. Aromatic C-H Stretching 4. Aliphatic C-H Stretching Key Differences:

interpret the IR spectrum for benzoin, benzil and benzilic acid. draw out compound on the corresponding spectrum and indicate the specific absorbance ( not the ranges from correlation table)for each type of bond. focus especially on amy OH bonds . some of the hydrogen bonding hroups display sharper than normal absorbance . Explain Why.(Hint -draw

Phosphorus pentachloride Formula: Lewis Structure (including appropriate resonance forms and formal charges) Number of valence electrons: Electron domain geometry Molecular shape: Polarity of individual bonds: Hybridization of the central atom: Bond angles: Overall polarity of molecule: Instructor initials Sulfur tetrafluoride Formula: Lewis Structure (including appropriate resonance forms and formal charges) Number of valence electrons: Electron

Identify the molecules that have a net dipole moment. Select all that apply: BF3 CCl4 (CH3)2O CH2Cl2 CO2 The Correct Answer and Explanation is : Let’s evaluate each molecule for its net dipole moment based on its molecular geometry and electronegativity differences: Molecules with a net dipole moment: I’ll also generate an image to visualize

Which of the following molecules have dipole moments? (Select allthat apply.) (a) CH2Cl2 CHCl3 CCl4 (b) N2O CO2 (c) NH3 PH3 For the molecules that are polar, indicate the polarity of eachbond and the direction of the net dipole moment of the molecule The Correct Answer and Explanation is : Let’s evaluate the polarity and

a. Construct an MO diagram for the formation of O2; use only the valence orbitals of the oxygen atoms. (b) Use the diagram to rationalize the following trend in OO bond distances: O2, 121 pm; [O2] þ, 112 pm; [O2] , 134 pm; [O2] 2, 149 pm. (c) Which of these species are paramagnetic? 2.11

Sort the following groups as ortho para and meta directing:Group-OCOREffect in EAS[Select]-NHCOCHortho para (electron donatir-COOR[Select]-NH2ortho para (electron donatir[Select]ortho para (electron donating, strong activating)meta (electron withdrawing, strong deactivating)ortho para (electron donating, moderate activating)meta (electron withdrawing, moderate deactivating The Correct Answer and Explanation is : To classify the given groups as ortho/para or meta directing, let’s analyze

How did federal housing programs discriminate against Americans of color? Claiming that Americans of color were at a greater risk of defaulting on FHA loans All of these are correct Creating self-fulfilling prophecies that racially integrated neighborhoods would have depreciating home values Redlining neighborhoods that included Americans of color The Correct Answer and Explanation is