1. Distinguish between reverse phase and normal phase separations. 2. What is the dynamic range for absorbance spectroscopy? What is the dynamic range for fluorescence spectroscopy? Which has the lowest LOD and why? 3. What types of molecules fluoresce? What is quenching and what makes a good quencher? 4. What is the underlying equation for all partition chromatography methods? Why?

Arrange the 0.15 M solutions of the following compounds in order of increasing acidity (least acidic first).

NH₄I                B. CH₃COONH₄          C. CH₃COOK           D. KCl                 E. CH₃COOH          

         F. KF                   G. HBr                          H. CHCl₂COOH        I. NH₃                  J. CF₃COOH

      ammonia,    K_b = 1.80

What is the key difference in the biosynthesis of purine ribonucleotides vs. the biosynthesis of pyrimidine ribonucleotides?

At a certain temperature, 0.4011 mol of N2 and 1.581 mol of H2 are placed in a 1.50L container. N2(g) + 3H2(g) −⇀↽− 2NH3(g) At equilibrium, 0.1401 mol of N2 is present. Calculate the equilibrium constant, Kc.

Calculate the molar solubility of magnesium fluoride in each of the following solutions:
a) pure water
b) 0.010 M potassium fluoride solution
c) 0.050 M solution of magnesium nitrate
d) Why are the results of parts (a) thru (c) different?

A). A mixture of methane and argon gases is maintained in a 8.34 L flask at a pressure of 2.24 atm and a temperature of 66 °C. If the gas mixture contains 3.59 grams of methane, the number of grams of argon in the mixture is............ g

. B). A mixture of xenon and hydrogen gases, in a 5.89 L flask at 13 °C, contains 12.5 grams of xenon and 0.288 grams of hydrogen. The partial pressure of hydrogen in the flask is.............. atm and the total pressure in the flask is............. atm.

what intermolecular forces are present in each of the substances?

EXAMPLES OF THERMODYNAMIC STATE FUNCTION WITH DEFINITION

A 1.000-L vessel contains a mixture of hydrogen, carbon monoxide and methane gases in unknown proportions at 23.3-bar and 25 °C. The gaseous mixture is found to have a mass of 13.70-g and a higher heating value of 494.90 kJ/mol. What is the composition of the gas?

Consider the titration of 65 mL of 1.75 M diethylamine, (CH3CH2)2NH (Kb = 1.3×10-3) with 0.25 M HCl. How many mL of HCl will need to be added to the diethylamine solution to reach a pH of 11.11?

The answer is NOT 455 mL or 45.5 mL

a.  Unhealthy exhaust results from the combustion of octane (C8H10) in automobile engines via the following reaction.

C8H18(l) + 25O2(g)  16CO2(g) + 18H2O(g)

Assuming the gasoline is pure octane and that a suburban dweller burns about 6.44 x 104grams of octane (about 20 gallons) per week. How many grams of CO2 are produced (per week) to warm the globe? At 25oC and 1.00 atm, how many ml of CO2 are produced? Give your answer in scientific notation,

b.   During combustion, N2 and O2 in the air react to make the nasty brown gas NO2which is smog. The smog rises up into the atmosphere, combines with water vapor and rains down as nitric acid (HNO3) to acidify all the lakes and streams and kill the fish and plants. The following reactions are relevant.
A. O2(g) + N2 (g)  2NO(g)

B. 2NO(g) + O2(g)  2NO2(g)

C. NO2(g) + H2O(g)  HNO3(aq) + NO(g)

Balance reaction C. Calculate the moles of HNO3 that form if 2.2 x 10-4 moles of NO2rise up into the air and react completely with an unlimited amount of water vapor.

  c.    A 200 mL sample of the lake water is collected titrated directly with 0.01M NaOH and it takes only 3 mL of the NaOH titrant to reach the equivalence point. Calculate the molarity (M) of HNO3 in the lake water.

d. Nitric acid is a strong acid and engages in the following ‘proton’ transfer(dissociation) reaction with water (in which it is dissolved).

HNO3(aq) + H2O(l)  H3O+(aq) + NO3-(aq)

Suppose the concentration of HNO3 in the lakewater is 0.08 mg/mL. Calculate the molarity of H3O+ and the pH of the lakewater.

Determine the pH of each of the following two-component solutions.

0.270 M NH4NO3 and 0.100 M HCN

8.0×10⁻² M RbOH and 0.120 M NaHCO3

8.2×10⁻² M HClO4 and 2.2×10⁻² M KOH

0.110 M NaClO and 5.50×10⁻² M KI

What is the pH of a solution that is 1.3 M NH3? ( Ka=5.70 x 10^-10 for NH4+).

For each of the following molecules, predict the molecular shape, give bond angles, hybridization and determine whether the molecule will be polar or non-polar.

a. CF4

b. BeH2

c. SeF6

d. XeOF2

Briefly explain how aqueous base can cause some water-insoluble compounds to become water-soluble. (b) Answer the same question for aqueous acid.