Experimental Organic Chemistry 1

-How do you know when you should use GC or HPLC?

-What's the difference between Reverse Phase HPLC and Normal Phase HPLC?

10) . Use the principles that you learned in Part ii to calculate the standard reduction potentials for each half-cell, given that the E° for Cu2+ + 2e-  Cu (s) is 0.34 V.Note that E° for a half-reaction is not dependent on the coefficients, provided of course that the reaction is balanced, i.e., E° for Ag+ + e- Ag (s) is the same as E° for Ag+ + 2e- 2 Ag (s)

Refers to Procedures Part III Step 9

* Pb results are most unreliable

Define the followings.
(a) collision flux
(b) Stokes law
(c) Fick's second law
(d) Einstein-Smoluchowski equation
(e) half-life of a first-order reaction
(f) Forster theory of resonance energy transfer
(g) Mechaelis-Menten mechanism

Consider the titration of 40.0 mL of 0.200 M HClO4 by 0.100 M KOH. Calculate the pH of the resulting solution after the following volumes of KOH have been added. a. 0.0 mL d. 80.0 mL b. 10.0 mL e. 100.0 mL c. 40.0 mL

answers are A) 0.699 B) 0.854 C) 1.301 D) 7.00 E) 12.15 I would just like to know how to do the work please and tbank you

A bottle filled with 0.5 L of an aqueous solution is at equilibrium with the gas containing 70 % (mole fraction) of nitrogen, N2, and 30 % of oxygen, O2. The temperature is 25 oC and the total pressure of the gas is 10 atm. The Henry’s Law constants for nitrogen and for oxygen in the solution are 6.1 × 10-4 mol L-1 atm-1 and 1.3 × 10-3 mol L-1 atm-1 .

(i) Calculate the partial pressure of oxygen and of nitrogen in the gas.

(ii) Calculate the molarity of nitrogen and oxygen dissolved in the solution.

(iii) Calculate the mass of nitrogen and the mass of oxygen released from the solution when the pressure in the gas was decreased to 1 atm at temperature 25 oC.

(iv) Calculate the volume of the gas released from the solution at pressure 1 atm and temperature 25 oC.

Iron reacts with chlorine gas according to the following balanced chemical equation:

2Fe(s)+3Cl2(g)→2FeCl3(s)

A) What mass of iron(III) chloride is produced when 101.08 g iron reacts with 185.42 g chlorine gas?

B) What is the percent yield of iron(III) chloride if 139.13 g of iron(III) chloride is actually obtained?

Using Excel, calculate a titration curve for a weak acid with a pKa of 3.57 with a
standardized NaOH solution of 0.1138 M. This curve should have a minimum of 20
calculated points; 15 before equivalence, equivalence, and 4 after equivalence. It is
STRONGLY recommended that you use the referencing features within excel to perform
these calculations. They may be done by hand, but will be extremely tedious! Submit
your (printed) results with an appropriately labeled figure and ALL calculations shown in
the immediately adjacent cell.

Formal concentration is 0.1000 M

Assume a 25.00 mL aliquot

Please show all work and the formulas you typed into excel

Which of the following is likely to have the greatest exothermic hydration enthalpy? A) Sr2+ B) Na+ C) Mg2+ D) Ca2+ E) K+

Which pair of aqueous solutions is given in order of increasing freezing point?

(1) 0.010m Na3PO4 < 0.030m NaCl

(2) 0.020m NaI < 0.030m glucose

(3) 0.010m CaCl2 < 0.020m KCl

(4) 0.010m Na3PO4 < 0.020m Na3PO4

(5) 0.020m glucose < 0.010m CaCl2

If a solution containing 84.670 g of mercury(II) nitrate is allowed to react completely with a solution containing 12.026 g of sodium sulfide, how many grams of solid precipitate will be formed?How many grams of the reactant in excess will remain after the reaction?

1. In this distillation experiment we start the experiment with 10 mL of liquid mixture ofcyclohexane and toluene. However, it is not possible to obtain all 10 mL back under thecurrent procedure particularly for fractional distillation. Explain why that is the case for distillation and in particular for fractional distillation.

2. How could you modify the experiment and collect all 10 mL of the startingmaterials.

3. Plot a theoretical distillation curve of temperature (y-axis) vs. volume in mL (x-axis) fora 15 mL of a mixture containing 60% 1-propanol and 40% 2-propanol. Are these twocompounds easier to separate by distillation than cyclohexane and toluene? Explain youranswer.

4. In this experiment you were asked to collect two fractions and early fraction and a latefraction. Which of the two fractions would be richer in cyclohexane? Would there be adifference between the percent of cyclohexane in the fractions collected from fractionalvs. simple distillation.

5. What method of purification would you use to purify methanol from a solution ofmethanol and NaCl? Be specific and explain your choice of method.

20 mL of .10 M HC2H3O2l solution in a small beaker is titrated with .10 M NaOH solution (at 25 C). Calculate the value of the equilibrium constant for this titration. Is it safe to assume that this titration reaction goes essentially to completion? Explain.

a bag of "bulldog ice melter" is made up of a mixture of calcium chloride and magnesium chloride, but the ratio of salts in not listed on the bad. A sample of salt mixture is added to 1000g of water. The concentration of chloride ions in the resulting solution is 2M. What is the molarity of the ions in this solution?

a. A student performed Part 3 of the lab. A 360 ppm Ca2+ standard required 22.34 mL of EDTA to reach the end point. Some well water from my grandma’s farm required 15.47 mL of EDTA. By proportionality to the 360 ppm standard, determine the total concentration of Ca2+ (in ppm) in my grandma’s well water?

b. What is the molarity of Ca2+ in the well water? (ppm stands for parts per million. 100 ppm Ca2+ represents 100 grams of Ca2+ in 1,000,000 grams of solution. Assume that the density of the solution is 1.00g/mL).

c. If the daily recommended amount of calcium in an adult’s (age 19 – 50) diet is 1,000 mg, how many liters of water would you need to consume to fully meet your daily calcium needs? (See http://www.nlm.nih.gov/medlineplus/ency/article/002412.htm for reference information.)

How will you determine the relationship between acid/base molarity and ∆H? Write specific equations for the reactions that you will use in this determination (at least 3). What variables will you need to keep constant in this determination?