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.

A student carried out reactions A through D as designed in Table 1 in your electronic lab manual, plotted log(rate) vs. log(I-) in EXCEL, and the linear regression yielded the following equation: y = 2..732x-1.032; and the plot of log(rate ) vs. log [IO3-] yield y = 1.368x-1.674.

The order for I- is?

The order for IO3- is?

Question #2 (5 pts): Compare the G proteins that acts in transducing the signal from b-adrenergic receptors, and Ras. What properties do they share? How do they differ? What is the functional difference between G_as and G_ai?