Consider two compounds for which t_m = 1 min, t₁ = 14.3 min and t₂ = 15.0 min. The peak widths at half heights are 13.0 sec and 14.9 sec, respectively. What are the peak widths? (This requires that you think about the mathematics of a Gaussian curve.) Calculate the resolution of this separation. How many theoretical plates does the column have for these analytes? What is the value of the selectivity factor, α?

given the reaction: Reaction of Dimedone and Benzaldehyde (2 Part)

overview Part 1:

Using a Pasteur pipet, add 0.2 g of benzaldehyde to 50 mL Erlenmeyer flask. 2. Add 8 mL of 1:1 ethanol/water and swirl the flask to mix the content. 3. Add 0.6 g of dimedone and 3 drops of piperidine, and 2-3 boiling chips 4. Boil gently for 5 min on a hot plate 6. at the end of 5 minutes let the mixture cool, followed by cooling in an ice bath to complete crystallization5. Collect crystals by vacuum filtration, washing with several 10 mL portions of ice cold 1:1 ethanol: water, Gently break the crystals with a spatula and let them sit on the vacuum for 30 min to dry.

overview Part 2:

Next if 250mg of product (from above) and 10 ml of absoulte enthanol were put into an erenmeyer flask, heated. Then 2.5ml of water and 6 drops of 6M HCL were added. The mixture was left to to continue  boiling. the flask was removed fro heat and water was added dropwise until the mixture becomes cloudy. The product is collected.

Questions:

1. why is it possible for dimedone to have two tauromers?

2. what spectroscopy methods can you use to prove the formation of tautomers?

3. why do you use piperdine during the first step of this reaction? could you use inorganic base instead?

4. what are the differences in IR between benzaldehyde and the product from part 2 (3,3,6,6-tetramethyl-9-phenyl-3,4,5,6,7,9-hexahydro-1h-xanthene-1,8(2h)-dione)

1. Which of the following buffers would be the best choice for a desired pH of 3.0:

            a. Acetic acid (pKa=4.74)

            b. HF (pKa= 3.14)

            c. Carbonic acid (pKa=6.37)

            d. Propanoic acid (pKa=4.85)

            e. Not enough information is given

2. A buffer (1L total volume) contains 0.15 moles ammonia and 0.25 moles ammonium chloride (pKa=9.26). What is the pH of that buffer solution? What is the pH after 0.0025 moles of KOH are added?

3. Which of the following makes the best buffer (assume equal volumes):

1. 0.1 M HNO₃ and 0.1 M LiOH
2. 0.1 M acetic acid (K_a = 1.8E-5) and 0.1 M NaOH
3. 1M acetic acid (K_a = 1.8E-5) and 0.0001 M sodium acetate
4. 0.1 M acetic acid and 0.1 M sodium acetate

4. When adding strong base to a buffer, which component of the solution is reacting with that strong base? Draw the reaction using HA for the weak acid and A- for the weak base.

Hi, would appreciate some answers and explanations to the below. If you have any sources to back up any points would be amazing but not necessary, Thanks!

1) Why is dichloromethane used to extract the clove oil from the distillate? (In reference to the extraction of eugenol from cloves via steam distillation).

2) Discuss the advantages of using dichloromethane compared to other organic solvents such as hexane, benzene, or diethyl ether?

3) What are some of the potential disadvantages of using dichloromethane as a solvent?

- Neon Emission Spectrum

A. Based on the emission spectrum for neon, what color would you predict for the neon tube? ______________________________

B. Search on Google for an image photo of a neon spectrum tube. Was your prediction correct? ____________________________

C.What is responsible for the color of a neon discharge tube?_________________________________________________________

- Sodium Emission Spectrum

A. The most prominent line in the emission spectrum of sodium is the result of a transition from a 3p to a 3s orbital. The wavelength of this line is 5893 Å. Convert this to nanometers (show your calculation) and give the color of light corresponding to this wavelength.

B. Based only on the color of the lines corresponding to the transitions, is the sodium 3p  3s transition of higher or lower energy than the n=3  n=2 transition in the hydrogen atom? Explain.

Predict a likely mode of decay for each of the following unstable nuclides. EXPLAIN why this might be so. a) Mo-109 b) Fr- 202 c) Rn- 196 d) Sb - 132 e) P - 27 f) Ru - 90

Assuming that no equilibria other than dissolution are involved, calculate the concentrations of ions in a saturated solution of each of the following (see Appendix J for solubility products).

(a) TlCl

(b) BaF2

(c) Ag2CrO4

(d) CaC2O4·H2O

(e) the mineral anglesite, PbSO4

Combustion analysis of a 13.42-g sample of the unknown organic compound (which contains only carbon, hydrogen, and oxygen) produced 36.86g CO2 and 10.06g H2O. The molar mass of estriol is 288.38g/mol .

Find the molecular formula of the unknown compound

Legal issues are important in the blood bank. Discuss how negligence and malpractice are cause for concern with laboratory/ phlebotomy professionals with both donor and patients.

The pKbpKb values for the dibasic base BB are pKb1=2.10 and pKb2=7.73.

Calculate the pH at each of the points in the titration of 50.0 mL of a 0.90 M B(aq) solution with 0.90 M HCl(aq).

What is the pH before the addition of any HCl?

pH=

What is the pH after the addition of 25.0 mL HCl?

pH=

What is the pH after the addition of 50.0 mL HCl?

pH=

What is the pH after the addition of 75.0 mL HCl?

pH=

What is the pH after the addition of 100.0 mL HCl?

pH=

What property enables you to classify an alcohol as primary, secondary, or tertiary?

What do all compounds classified as aromatic compounds have in common and why are they called aromatic?

A gaseous mixture of propane, carbon dioxide and hydrogen with a mixture total mass m = 188 g occupies a volume V = 33 L at t = 88

2-6.

(i) Considering the effects of the ionic strength, use Excel to calculate the cell voltage of Zn | ZnSO₄ (x M) || PbSO₄(s) | Pb, where x: 1´10^-4, 5´10^-4, 1´10^-3, 5´10^-3, 0.01, and 0.05 M.

PbSO₄ → Pb²⁺ + SO₄²⁺, K_sp = 1.69 ´ 10^-8

Pb²⁺ + 2e^- → Pb, E^o = -0.13 V vs. NHE

Zn²⁺ + 2e^- → Zn, E^o = -0.76 V vs. NHE

(ii) Recalculate the cell voltage when 1.0 M KNO₃ is present in the anodic half-cell.

(iii) Plot the results of (i) and (ii) against log(x) together on one sheet.

(iv) Give conclusions on the difference between the curves.

Thank you.