Phosphoric acid is a triprotic acid with the following pKa values:

pKa1=2.148 pKa2=7.198 pKa3=12.375

You wish to prepare 1.000 L of a 0.0200 M phosphate buffer at pH 7.720. To do this, you choose to mix the two salt forms involved in the second ionization, NaH2PO4 and Na2HPO4, in a 1.000 L volumetric flask and add water to the mark. What mass of each salt will you add to the mixture?

mass NaH2PO4= ________g mass Na2HPO4= __________g

What other combination of phosphoric acid and/or its salts could be mixed to prepare this buffer? (Check all that apply).

H3PO4 and NaH2PO4

H3PO4 AND Na2HPO4

H3PO4 and Na3PO4

NaH2PO4 and Na3PO4

Na2HPO4 and Na3PO4

Answer the following questions:

• Define the following terms as used in NMR:
  • integration
  • chemical shift
  • magnetic equivalence
  • splitting (multiplicity)
• List the properties and all known hazards of deuterated chloroform
• Why do we use a deuterated solvent instead of regular solvent (CHCl3 vs CDCl3 for example)?

Balance the following equation in acidic solution using the lowest possible integers and give the coefficient of H+. MnO4-(aq) + H2S(g) → Mn2+(aq) + HSO4-(aq)

When an optical spectroscopic transition is measured, either by emission or absorption, a so-called lineshape of given intensity and frequency dependence is obtained. For any spectroscopy there exist quantum mechanical or other basic connections to all of the experimental parameters that determine the lineshape. List these experimental parameters and explain how they are related to the previously mentioned connections.

When using radial paper chromatography to separate ink pigments, does the least soluble or most soluble pigment travel the furthest distance? The solvent is water.

How many grams of dipotassium succinate trihydrate (K2C4H4O4·3H2O, MW = 248.32 g/mol) must be added to 600.0 mL of a 0.0481 M succinic acid solution to produce a pH of 5.946? Succinic acid has pKa values of 4.207 (pKa1) and 5.636 (pKa2).

1.Which type of radioactive emission is analogous to an electron being emitted?

positron, neutrons, alpha particle, gamma rays, beta particle

2. Which isotope is naturally radioactive?

⁴₂H, ²₁H, ¹⁶₈O, ²³⁴₈₈Ra

3. the half life of protactinium-231 is 3.5x10⁴ years. How long will it take for 10.4 grams of Pa-231 to decay to 2.6 grams?

4. the half life of phorphorous-33 is 25.3 days. How long will it take for 64 grams of p-33 to decay to 1.0 grams?

5. the half life of sr-83 is 32.4 hours. how many emissions are produced when 20 g of strontium-83 decas to 4.0 grams?

1. One liter of saturated actinium hydroxide solution contains .021 g of dissolved Ac(OH)3. Calculate Ksp for Ac(OH)3

CORRECT ANS: 8.8E-16 solve and explain pls

2. For a particular reaction at STP ( 298 K) CHANGE IN H= -297kJ/MOL AND CHANGE IN S= -113.3 J/MOL*K. At which of the following temperatures would the reaction become spontaneous?

CORRECT ANS: 2450 K

Solve and show steps

3. Rate data have been determined at a particular temp for the overall reaction 2NO + 2h2-> N2 + 2H2O IN WHICH ALL REACTANTS AND PRODUCTS ARE GASES

TRIAL INITIAL [NO] INTIAL [H2] INITIAL RATE (MS^-1)

1 .1M .2M .0150

2 .1M .3M .0225

3 .2M .2M .0600

(which column do you divide by what to get the power for determining that rate law expression?

4. Molten AlCl3 is electrolyzed for 5.0 hours with a Current of .4 Amps. Metallic Al is produced at one electrode and chlorine gas (Cl2) is produced at the other. How many grams of aluminum are produced?

CORRECT ANS: 0.67 g (EXPLAIN AND SHOW WORK PLS)

Question 5

A. How many mL of 0.1 M CH3COONa must you add to 35.0 mL of 0.50 M CH3COOH to make a buffer of pH 4.7? [pKa of H3COONa is 4.75]

B. Use the Henderson-Hasselbalch equation to calculate how many mL of 0.1 M HCl must you add to 100 mL of 0.10 M Tris base to make a buffer of pH 8.8? [pka of Tris Base is 8.08]

C. What is the pH when 25.0 mL of 0.200 M of H3COONa has been titrated with 35.0 mL of 0.100 M NaOH? Write out the balanced chemical equation.

D. You need to produce a buffer solution that has a pH of 4.68. You already have solution that contains 15.0 mmol of H3COONa. How many millimoles of H3COONa should you add to this solution?

The orbital potential energies for the 4s and 4p of Br are -18.65 ev and -12.49ev, respectively. Recall that the H 1s is -13.61ev. The MO diagram for HBr is not exactly the same as HF. Draw the MO diagram for HBr, including energy levels, each orbitals shape, each orbitals character (meaning what atomic orbitals contribute to each M.O. and how much), symmetry labels (e.g.  and , * and *), indicate the HOMO and LUMO, the bond order (show your work), whether the molecule is paramagnetic or diamagnetic. Now write a couple paragraphs comparing and contrasting the MO diagrams of HF and HBr in great detail (this last part is worth 50% of the points).

Consider the following species: Na, Mg, Cl^-1,S,Cl,Ar,Na^+

(a) Order the above species in order of increasing atomic/ionic radius.

(b) Order the above species in order of increasing electron affinity

Showing each step: Use the molecular weight of Tyrosinase, 128,000, to determine how many micromoles of Tyrosinase are in the tubes. Assume 5 mL of Tyrosinase is used and that it has a concentration of 15 mg/mL.  

Quinine occurs naturally in the bark of the cinchona tree. For centuries, it was the only treatment for malaria. Quinine contains two weakly basic nitrogen atoms, with Kb1=3.31 x 10^-6 and Kb2=.00000000135 at 25 C. Calculate the pH of a .011 M solution of quinine in water.