Category: Chemistry

The reaction of CrCl3 with liquid NH3 to give yellow [Cr(NH3)6]Cl3 often has a low yield,
since the reaction tends to stop with the production of pink [Cr(NH3)5Cl]Cl2. However,
adding a small piece of Na metal to the liquid NH3 results in complete conversion of the
CrCl3 to [Cr(NH3)6]Cl3. Offer two plausible explanations of this rate enhancement for the
final step of the substitution process
2- Write a hypothetical inner-sphere redox mechanism for the reaction of [Cr(OH2)6]2+ with cis-
[Co(en)2I2]+ in acid solution to give (ultimately) cis-[Cr(OH2)4I2]+, Co2+
(aq) and en. What
evidence could support this mechanism and why?
3-Consider reduction of the following cobalt complexes [Co(NH3)5(L)]3+ (L = pyridine (I),
NC5H4-p-CH2NH2 (II), NC5H4-p-CONH2 (III)) by labile [Cr(OH2)6]2+
.
a). Which cobalt complex is least likely to be reduced by an inner-sphere mechanism?
b). The reduction of III proceeds with a rate constant of k = 17.4, while the reduction of I
proceeds with a rate constant of k = 4.0 × 10-3
. What is a likely explanation of the difference?
Requirements: 1page

Draw the products that are expected when β-D-allopyranose is treated with each of the following
reagents:
a. Excess CH3I, Ag2O
b. Excess acetic anhydride, pyridine
c. CH3OH, HCl

Draw the products that are expected when β-D-allopyranose is treated with each of the following
reagents:
a. Excess CH3I, Ag2O
b. Excess acetic anhydride, pyridine
c. CH3OH, HCl

9. a. Identify the two aldohexoses that are obtained when D-arabinose undergoes a Kiliani–Fischer synthesis.
b. Identify the two aldohexoses that will undergo a Wohl degradation to yield D-ribose. Draw a Fischer
projection of the open-chain form for each of these two aldohexoses.

a. When treated with sodium borohydride, D-glucose is converted into an alditol. Draw the structure of
the alditol.
b. When D-galactose is heated in the presence of nitric acid, an optically inactive compound is obtained.
Draw the structure of the product and explain why it is optically inactive.

10. Isomaltose is similar in structure to maltose, except that it is an alpha-1,6 glycoside, rather than an alpha1,4 glycoside. Draw the structure of isomaltose.

Journal article outline: Abstract, Introduction, Material and methods, Result (I will upload the laboratory result of cocaine detection by LC-MS technique), Discussion, and Conclusion, finally Referances.

Q. Using lead exposure paint, prepare a presentation with a 5 minute voice over it – to give your
fellow students exploring the possible impacts of climate change on your toxin.
For example, climate change plus lead = more dry weather, more dust, more lead in dusty places inhaled. Another example: increased risk of PAH exposure as CC increases the risk of bushfires. Your presentation needs to be referenced.
Please make Powerpoint include Powerpoint generic note each page. Do not include title page.
Please use Blank Presentation (no design)
References: APA7 (last page)

disregard anything that includes lab 11. In this lab report I need an abstract, introduction, experimental procedure, and results and discussions. It needs to be cited with journal articles.

You were asked to evaluate the results of GPC analysis of PMMA (poly[methyl methacrylate]) polymer. Separation was made on PLGel universal column (styrene-divinylbenzene 100 – 107 separation range), RI detection, and eluent – THF, calibration by polystyrene standards. Weight and number average values were calculated directly from chromatogram. Are the calculated Mwand Mn values, correct? Explain why.
2/ You are separating benzene, toluene and ortho-nitrophenol on RP column with acetonitrile/water as eluent. How the variation of the eluent composition (% of acetonitrile in water) will affect the selectivity between benzene and toluene and between o-nitrophenol and benzene? Explain.