For the diprotic weak acid H2A, Ka1 = 2.2 × 10-6 and Ka2 = 8.3 × 10-9. What is the pH of a 0.0700 M solution of H2A? What are the equilibrium concentrations of H2A and A2– in this solution?

Choose the correct definition for an intrinsic semiconductor with an example.

1. a conductive material of an element with the addition of dopant (0.0001% Si in Al )
2. a conductive material of an element with the addition of dopant (0.0001% Al in Si )
3. a material that naturally can have electrons move across the band gap ( Al )
4. a material that naturally can have electrons move across the band gap (pure silicon)

Choose the correct definition for an extrinsic semiconductor with an example.

1.a conductive material of an element with the addition of dopant (0.0001% Si in Al )
2.a material that naturally can have electrons move across the band gap (pure silicon)
3.a conductive material of an element with the addition of dopant (0.0001% Al in Si )
4.a material that naturally can have electrons move across the band gap ( Al )

Match Column B Items with Column A Items ( match B is from A-i will be matched with column A)

Column A

______Reagents used to prepare the nonMarkovnikov product

______Reagent used to prepare an epoxide

_______Reagent used to carry out vigorous oxidation

______Reagent used to form dichlorocarbene

______Reagents used to convert alkynes to methyl ketones

____1,1-disubstituted substituents

______1,2- disubstituted substituents

Column B

a. KOH b. m-chloroperoxybenzoic acid c. hot alkaline Mn04- d.NaNH2 e. Vicinal

Methanol (CH₃OH) is made by reacting gaseous carbon monoxide (CO) and gaseous hydrogen (H₂).

A. What is the theoretical yield of methanol if you react 37.5 kg of CO(g) with 4.60 kg of H₂(g)?

B. You found that 1.83 x 10⁴ g of methanol is actually produced. What is the percent yield of methanol?

31. Which of the following describes the distribution of the polar and nonpolar portions of lipids in the lipid bilayer? A). Both polar heads are on the inside of the bilayer and both hydrophobic tails are on the outside of the bilayer. B). Both polar heads are on the outside of the bilayer and both hydrophobic tails are on the inside of the bilayer. C). Both the inside and outside of the bilayer consist of alternating polar heads and nonpolar tails. D). Some polar heads are on the inside of the bilayer and some are on the outside; the hydrophobic tails are similarly distributed.

33. Which describes the isoelectric point of an amino acid? A). The degree of ionization of the amino acid at pH 7. B). The pH at which there is no net charge for the amino acid. C). The pH at which the ionized form predominates. D). The pH at which the amino acid is present as the dipolar ion. CH2 – CONH2 

34. Asparagine (Asn) has an isoelectric point (pI) of 5.4, (H3N+ ¾CH¾COO- ). Select the correct Zwitterion structure of asparagine in a solution with a pH of 10. CH2 – CONH2 CH2– CONH2   A). H2N¾CH¾COO- B). H3N+ ¾CH¾COOH CH2– CONH2 CH2– CONH2   C). H2N¾CH¾COOH D). H3N+¾CH¾COO-

35. Which functional group is involved in linking together the amino acids of proteins? A). amine B). anhydride C). carbonyl D). carboxyl

36. Select the correct three-letter abbreviation for the order of amino acids in this tripeptide. O H O H O      H3N+  CH  C  N  CH  C  N  CHCO-    CH2OH CH3 H A). AlaGlySer B). GlySerAla C). SerAlaGly D). AlaSerGly

37. The secondary structure of proteins depends primarily on which property of amino acids? A). disulfide bonds B). hydrogen bonds C). amide bonds D). polar side chains

38. The beta-pleated sheet represents what level of protein structure? A). Primary B). Secondary C). Tertiary D). Quaternary

39. The following will denature proteins EXCEPT A). Agitation B). Acids and bases C). Heavy metal ions D). Freezing temperature

40. Which of the following is a structural protein? A). cellulose B). collagen C). hemoglobin D). insulin

41. In which of the following is the amino nitrogen also part of the side chain? A). cysteine B). glycine C). proline D). tryptophan

Part A. What mass of carbon dioxide is produced from the complete combustion of 5.70×10⁻³ g of methane?

Part B. What mass of water is produced from the complete combustion of 5.70×10⁻³ g of methane?

Part C. What mass of oxygen is needed for the complete combustion of 5.70×10⁻³g of methane?

Express your answer with the appropriate units.

This question is based on the mass spectrum of diethyl sulfide (CH3CH2SCH2CH3) which can be found at this link... http://webbook.nist.gov/cgi/cbook.cgi?ID=C352932&Mask=200 You will need java to see this spectrum! Identify the ion fragment that has a mass of 29.

a) C2H5SC2H5+

b)C4H10+

c) C2H5+

d) S+

Cryogenic liquids (liquid N2, He, etc) are typically stored in Dewar flasks (fancy thermos bottles) that consist of mirrored glass walls (to reduce radiative heating) separated by vacuum (a cylinder within a cylinder). How long would a liter sample of liquid argon last in a flat bottomed cylindrical Dewar with an inner radius of 5cm and height of 20cm and an outer radius of 10cm and height of 25 cm assuming that the only energy transfer that occurs is radiative between the walls of the Dewar (the top surface does not receive any radiation). The emissivity of silvered glass is 0.02 over all wavelengths, the outer surface of the Dewar is at 300K, the temperature of liquid Argon is 87 K, the density of liquid argon is 1.40 g cm3 , and the latent heat of vaporization is 1200 J/g. , The latent heat of vaporization is a measure of how much “extra” energy is required to vaporize a substance at its boiling point (the boiling point of argon is 87K). (Assume that all of the energy impinging on the inner cylinder is used to vaporize the Argon).

Determine the pH of a solution when 21.5 mL of 0.021 M HNO3 is mixed with 17.5 mL of

A) 0.0070 M NaOH.

B) distilled water.

C) 0.0070 M HCl

D) 0.084 M KOH.

compute the following:

(a) Calculate the wavelengths for the Paschen series for Hydrogen

(b) If the average speed of a Hydrogen electron is 4.0*10^6 m/s with a 0.95% uncertainty. What is the uncertainty of its position? ( Hint: the mass of an electron is 9.109*10^-31)

Determine Delta G for the following reactions.

a) Antimony pentachloride decomposes at 448oC. The reaction is: SbCl5(g)-->SbCl3(g)+Cl2(g)

An equilibrium mixture in a 5.00 L flask at 448oC contains 3.85g of SbCl5, 9.14g of SbCl3, and 2.84g of Cl2.

b) Chlorine molecules dissociate according to this reaction: Cl2(g)-->2Cl(g)

1.00% of Cl2 molectules dissociate at 975K and a pressure of 1.00 atm.

calculate the de Brolie wavelength for a molecule of (Ch_4) at -5degree c.

What is the role of kinetic energy quantization in covalent bond formation? [keywords: particle-in-a-box, length, quantum state, energy, kinetic, hydrogen atom, hydrogen molecule, covalent bond energy...]

.   Draw a block flow diagram for a petroleum refinery that includes three different separation processes, five different conversion processes along with one or more finishing processes, and one supporting process to produce altogether nine commercial fuels and materials from a sour crude oil. Clearly label all the feedstocks, processes, and products on your diagram including the type of process (separation, conversion, finishing, and support) and the intermediate products.    Make sure that all processes are correctly connected. Write down the principal objectives of this refinery.

How do quantum mechanics and numbers play into both Bohr's model of the atom and Heisenburg's model?