CHROMATOGRAPHY

In running a TLC analysis of ferrocene and acetylferrocene, the two substances were analyzed on a TLC plate in 3 different solvents (1:1 petroleum ether/diethylether, and petroleum ether and diethylether, respectively). What would be some clues that the samples of ferrocene and acetylferrocene being used in this analysis were impure?

A scientist measures the standard enthalpy change for the following reaction to be -613.2 kJ :

P₄O₁₀(s) + 6 H₂O(l)-->4H₃PO₄(aq)

Based on this value and the standard enthalpies of formation for the other substances, the standard enthalpy of formation of H₃PO₄(aq) is kJ/mol.

How many milliliters of water vapor, H₂O_(g), measured at 318 ^oC and 735 torr, are formed when 33.6 mL of NH₃ at 825 torr and 127 ^oC reacts with oxygen according to the following equation:

4NH_3(g) + 3O_2(g) --> 2N_2(g) + 6H₂O_(g)

1.50L reaction vessel was initially filled with 0.150moles of CO and 0.300moles of H2. After equilibrium is established, the vessel is found to contain 0.119moles of CO. What is the equilibrium constant for this reaction? The reaction is: CO(g) + 2H2(g) ↔ CH3OH(g)

Description: Our solar system is very diverse when it comes to the gas composition on our planets. On Mercury, which has almost no atmosphere, the pressure is less than 10-14 bar. Venus on the other hand has a much more dense atmosphere than earth, with a pressure of 92 bar. Instructions: Write a response to the following prompt and then respond to your peers.

Would having different atmospheric pressures have an effect on the accuracy of gas laws? If so, which planets would be the most reliable and which would be the least?

Balance the following oxidation reduction reaction under acidic conditions. Show your work. MnO4− + H2SO3→ SO4 2− + Mn2+

What is the difference between the endpoint and stiochiometric point in a strong acid/base titration?

A) The endpoint is when the pH is exactly 7

B) The stoichiometric point is when the pH is exactly 7

C) The endpoint and the equivalence point are the same thing

D) None of these answers is correct

I want an explanation to why it is B.

Iodine - 131 is used in medical imaging. Iodine - 131 has a half-life of 8days. How much Iodine - 131 remains in a patient's system after 1 month?

Answer the following short answer questions.

A) What feature of a reaction would ensure that its rate would respond to a pressure jump?

B) Compare and contrast the pre-equilibrium and steady state approximations.

C) Explain the role of the salt-bridge in an electrochemical cell.

How much heat is required to convert solid ice with a mass of 605 g and at a temperature of -12.5 °C to liquid water at a temperature of 55.5 °C? (The specific heat of ice is c_ice = 2100 J/kgK, the specific heat of water is c_water = 4186.8 J/kgK, and the heat of fusion for water is: L_f = 334 kJ/kg.)

1. A student prepares two aqueous solutions. For each solution:

-Calculate the molarity.

-Write a chemical equation representing the formation of the solution. Be sure to include phase labels and to show any ions that dissociate.

-Draw a molecular picture of the solution showing any ions, solute molecules and water molecules.

A. 2.91 g Na₂CO₃ to make 25.0 mL solution.

B. 6.14 mL ethanol (d=0.789 g/mL) to make 75.0 mL of solution.

C. Which solution is more concentrated?

D. Identify each solution as a strong, weak, or non-electrolyte.

nitrogen and hydrogen combine at high temperature, in the presence of a catalyst, to produce ammonia. N2(g)+3H2(g) > 2NH3(g). assume 0.270 mol of N2 and 0.877 mol of H2 are present initially. Questions- 1. after complete reaction, how many moles of ammonia are produced? 2. how many moles of H2 remain? 3. how many moles of N2 remain? 4. what is the limiting reactant(hydrogen or nitrogen)?

1. The effect of an inhibitor on an enzyme was tested and the experiment gave the results below. Plot on Excel the data using a double-reciprocal plot (Lineweaver-Burke), determine K_m and V_max of the no inhibitor and each type of inhibitor and the type of inhibition that is occurring.

[S] µM      V (µmol/min) V (µmol/min) V (µmol/min)

                  with 0.0 nM    with 25 nM     with 50 nM

                  Inhibitor          Inhibitor          Inhibitor

______      ___________ ___________ ___________

                     0.4          0.22                0.21                 0.20

                     0.67        0.29                0.26                 0.24

                     1.00        0.32                0.30                 0.28

                     2.00        0.40                0.36                 0.32

Draw the electron-group geometry for HNO3, in which hydrogen is attached to one of the oxygens and all oxygens are attached to nitrogen. To simplify, ignore the hydrogen when you name the molecule's shape. Draw the Lewis dot structure.