Homework Help for Chemistry

1. Calculate %u0394G%u2218 at 298 K for the following reactions.

A. Ca (s) + CO2 (g) + 1/2O2 (g) --> CaCO3 (s)

B. 2KClO3 (s) --> 2KCl (s) + 3O2 (g)

C. CH4 (g) + 3Cl2 (g) --> CHCl3 (g) +3HCl (g) (delta Gf forCHCl3 is -70.4 kJ/mol)

2. Determine %u0394G%u2218 for the following reaction:
Fe2O3(s)+3CO(g)%u21922Fe(s)+3CO2(g)
Use the following reactions with known %u0394G%u2218rxnvalues:
2Fe(s)+32O2(g)%u2192Fe2O3(s), %u0394G%u2218rxn = -742.2 kJ
CO(g)+12O2(g)%u2192CO2(g), %u0394G%u2218rxn = -257.2 kJ

The addition of bromine to trans-p-anisalacetophenonegives a single diasteromer.

a. Using curved arrows to symbolize the flow of electrons andsuitable stereochemical drawings, show the mechanism of thisreaction.

b. How does the mechanism you proposed in Parta support the formation of the racemic form of a singlediastereomer?

Please explain your answer for 5 stars.

In each reaction box, place the best reaget and conditions fromthe list below.

From the list of possible intermediates show at the right,choose those that would be:

a) an intermediate in the formation of ortho-toluidine

b) an intermediate in the formation of meta-toluidine

A rock contains 270 micro mol of 238^U (t1/2 = 4.5e9 yr) and 110micro mol of 206^Pb. Assuming that all the 206^Pb comes from decayof the 238^U, estimate the rocks age (in yr).

Laboratory Questions:

1- Part D.1 What is the fate of Zn2+ in the experiment?Explain.

2- Part D.2 Instead of 6 M HNO3being added to the solution, 6 M HCl is added (both are strongacids). How will this affect the test for the presence of copper(II) ion in the solution? Explain.

3- Part D.3 Instead of conc NH3 being added to thesolution, 6 M NaOH is added (both are bases). How will this affectthe test for the identifecation of copper (II) ion in the solution?Explain.

4- Part E.1 Instead of 6 M NH3 being added to thesolution, 6 M NaOH is added (both are bases) before the addition ofK2C2O4. What would be the appearance of the solution?Explain

I have to do a homework for a lab about TLC(Thin layerChromatography)

and I need help for these questions

imagine that you have called as a witness to defend youridentification. what sources of error exist that may weaken yourconclusion?

discuss the three different solvents(ethyl acetate, ethanol, andwater) in terms of polarity and what your results indicate aboutthe degree of polarity that seems to be best for this particularanalysis?

Imagine that, at the trail, you are asked to explain why somepigments moved further than others on the TLC plate. Explainthis.

Explain what condition are necessary to get a good separation ifcomponents when doing a TLC analysis?

Techniques including X-ray crystallography, spectroscopy andmagnetic measurements demonstrate that mercury (1) is almost alwaysfound as the dimer, H²⁺. A concentration cell is onein which the only difference between the two half cells is theconcentration of a reacting species. The following concentrationcell was used for all measurements:

Hg | Hg(I) (C_L) || Hg(I)(C_R) |Hg

WhereHg(I) is present at a concentration C_L In the left half-cell and at aconcentration C_Rin the right half-cell. Stock solution A wasprepared from 2.8 g or mercury (I) nitrate mono-hydrate, which iseither HgNO₃*H₂O (FW 280.61) if Hg (I) is monatomic, orHg₂(NO₃)₂*2H₂O (FW 561.22) if Hg(I) is diatomic. The salt was dissolved in100.0 mL of 0.16 M HNO₃containing a few drops of liquid Hg to preventoxidation of Hg(I). Solution B was a 1.6 MHNO₃.Five concentration cells in the following table were set and theirvoltage was measured.

b) Write the 2 half-reactions for theconcentration cell and write the Nernst equation for the completecell if Hg (I) is monatomic. (i.e. Hg⁺)

c) Write the 2 half-reactions forthe concentration cell and write the Nernst equation for thecomplete cell if Hg (I) is diatomic. (i.e.Hg²⁺)

a. what accounts for the large amount of ring strain incyclopropane and cyclobutane? (Hint: what bond angle does an sp^yhybridized carbon prefer? What angles are necessary for each of thegeometric shapes you are building?)

b. Are the C-H bonds in each cyclic structure staggered oreclipsed?

cyclobutane:

cyclohexane:

which conformation appears to be the most favorable arrangementof cyclohexane? Draw the double Newman projection for the chairconformation.

Draw the products formed.

Using tabulated data, and the fact that the boiling point ofmercury is 337.7C, calculate S for mercury vapor.