A 236.4 mL sample of water contains 0.0294 g of NaCl. Calculate the concentration in ppm.

concentration = ___ ppm

Demonstrate, how to calculate the drift time in a TOF mass spectrometer, if the acceleration voltage is known.

a solution prepared by mixing 60ml of .1m agno3 and 60ml 0f .1m tino3 was titrated with .2M nabr in a cell containing a silver indicator electrode and a reference electrode of constant potential .175 v. the reference electrode is attached to the positive terminal of the potentiometer, and the silver electrode is attached to the negative terminal. the solubility constant of tibr is ksp=3.6x10^-6 and the solubility constant of agbr is ksp=5x10^-13.

AgBr precipitates first

the following expression shows how the cell potential E depends on {ag+]      E=.175-[.799-.05916log(1/[ag+])]

1. Calculate the first and second equivalence points of titration.

2. what is the cell potential when the following volumes of .2M nabr have been added: a)1ml, b)16.8ml, c)29ml, d)29.9ml, e)30.3ml, f)46.8ml, g)60ml, h)63.6ml

(Chemical Engineering) Why would any gas at STP be considered ideal?

(8) When 100.0 mL of weak acid HA were titrated with 0.09381 M RbOH, 27.36 mL were required to reach the equivalence point.

(a) Find the molarity of HA.

(b) What is the formal concentration of A- at the equivalence point?

(c) The pH at the equivalence point was 10.99. Find pK_a for HA.

(d) What was the pH when only 19.47 mL of RbOH has been added?

A solution containing 50 mL of 2 x 10 -3 M of an indicator H 2 In is measured to have an absorbance of 0.240 at 540 nm with a 1 cm thick cuvette. After 50 mL of 2.8 x 10 -3 M NaOH was added to the solution, the absorbance became 0.048. A second solution containing 50 mL of 2 x 10 -3 M of the same indicator in its basic form, In = , is measured to have an absorbance of 0.060 at 540 nm. After 50 mL of 6 x 10 -4 M HC1 was added, the absorbance became 0.039. The indicator is known to have dissociation constants of K 1 = 4.0 x 10 -7 , K 2 = 6.67 x 10 -8 .

a) What is the pH of the original solution of H 2 In?

b) What is the pH after the NaOH was added to it?

c) If I mix the first and second solutions together (i.e. the H 2 In solution with the NaOH added plus the In = solution with the HC1 added), what pH will I get?

d) What are the molar absorptivities of H 2 In, HIn - , and In = ?

e) What is the absorbance of the mixed solution in part c)?

Using S? values from Appendix C in the textbook, calculate ?S? values for the following reactions. 5 significant figures please!!!

C2H4(g)+H2(g)?C2H6(g)

N2O4(g)?2NO2(g)

Be(OH)2(s)?BeO(s)+H2O(g)

2CH3OH(g)+3O2(g)?2CO2(g)+4H2O(g)

sodium azide (65.01 g/mol) energetically decomposes to give sodium metal and nitrogen gas. according to the eguation : 2NaN3 (s)\rightarrow 2 Na (s) + 3 N2 (g) . what the mass of sodium azide is needed to generate 20.0L of nitrogen gas (p= 1.25 g/L)?

On the basis of your research, respond to the following: What is the difference between biochemical, pharmaceutical, and diagnostic chemical reactions in healthcare? What is a specific example that exists for each of these chemical reaction types above and why might it be of importance to healthcare professionals? List a balanced chemical equation for each of these chemical reaction types and explain how it is used in your example above.

Consider the hydrocarbons whose structures are listed below. Which of these molecules would be planar, meaning that all of the atoms must always lie in the same plane? Explain your answer in terms of orbital hybridizations.

Given hydrocarbons: Cyclohexane, Benzene, Methlbenzene

1. Give the best product of the following reaction:

HBr excess

A. B. C. D. E. Br Br Br Br Br Br Br

2. What configurations are found in the product(s) of the reaction below:

A. 1R, 2R only.

B. 1S, 2S only.

C. and equal mixture of 1R, 2S and 1S, 2S.

D. and equal mixture of 1R, 2R and 1S, 2S.

E. and equal mixture of 1R, 2R and 1R, 2S.

3. Identify the most stable conformation of butane:

A. anti

B. eclipsed

C. gauche

D. totally eclipsed

E. adjacent

4. How many distinct alkene products are possible when the alkyl iodide below undergoes an E2?

A. 1

B. 2

C. 3

D. 4

E. 5

5. The carbon-carbon triple bond of an alkyne is composed of ________.

A. three σ bonds

B. two σ bonds and one π bond

C. one σ bond and two π bonds

D. three π bonds

6. Which of the following would have the highest boiling point?

A. B. C. D. E.

7. Which of the compounds have bonds that are predominantly ionic?

A. KCl

B. CF4

D. NH3

D. both A and B

E. both B and C

8. How many asymmetric centers are present in the compound below?

O

9. What is the thermodynamic product of the following reaction?

E.

Cl Cl

Cl

10. Which of the following compounds is the major product when 1-hexyne is treated with excess HBr?

A. 1,1-dibromohexane

B. 1,1-dibromohexene

C. 1,2-dibromohexene

D. 1,2-dibromohexane

E. 2,2-dibromohexane

11. Give the best product for the reaction.

Br

2

A. OH B. Br C. HOD. OH E. Br

Br

Br OH BrBr

12. Give the IUPAC name for the following structure:

A. 3-chloro-2-methylcyclohexanol

OH B. 2-methyl-5-chlorocyclohexanol

C. 1-chloro-4-methylcyclohexanol

D. 5-chloro-2-methylcyclohexanol

E. 2-methyl-3-chlorocyclohexanol Cl

13. What is the major organic product of the following reaction?

A. 2,3-dimethyl-1-hexene

B. 2,3-dimethyl-2-hexene

C. 2-isopropyl-1-pentene

D. (Z)-2,3-dimethyl-3-hexene

Br

E. (E)-2,3-dimethyl-3-hexene

14. Which of the following statements concerning SN2 reactions of alkyl halides is not correct?

A. The rate of reaction depends on the concentration of the nucleophile.

B. The rate of reaction depends on the concentration of the alkyl halide.

C. The rate of reaction of a particular alkyl bromide depends on the steric accessibility of the carbon of the C-Br bond.

D. All alkyl iodides react more rapidly than all alkyl chlorides.

E. The rate of the reaction depends on the relative nucleophilicity of the nucleophile.

15. Which of the alkyne addition reactions below involves an enol intermediate?

A. hydroboration/oxidation

B. treatment with HgSO4 in dilute H2SO4

C. hydrogenation

D. both A and B

E. both A and C

16. Which of the following is a true statement

A. All chiral molecules possess a plane of symmetry.

B. All achiral molecules are meso.

C. All molecules which possess a single chiral center of the S configuration are levorotatory.

D. A mixture of achiral compounds will be optically inactive.

E. All molecules which possesses two or more chiral centers will be chiral.

17. The reagent needed to convert 2-butyne to cis-2-butene is:

A. H2/Pt

B. H2/Lindlar's catalyst

C. Li/NH3

D. Na/NH3

E. H+/zinc dust

18. Which compounds shown below is/are the products of this reaction:

HO-

Br heat

I. II.

A. I only.

B. II only.

C. I and II are of equal yield.

D. I is major, II is minor.

E. I is minor, II is major.

19. Which of the following structures, including formal charges, is correct for diazomethane, CH2N2?

A. B.C.D.E. +3 -3

20. Name the following compound:

OH A. 3-heptyn-6-ol

H2C N N H2C N N H2C N N H2C N N 3

CH3CH2C CCH2CHCH3 B. 3-hepten-6-ol

C. 4-hepten-2-ol

D. 4-heptyn-2-ol

E. 4-heptan-1-ol

21. Which of the following is a correct statement considering thermodynamic vs. kinetic control of organic reactions?

A. When a reaction is under thermodynamic control, the relative amounts of products depend on the activation energies of the steps leading to their formation. B. The kinetic product always predominates when the reaction is reversible.

C. Higher temperatures and longer reaction times typically favor the kinetic product over the thermodynamic product.

D. When the products are in equilibrium under the reaction conditions, the relative amounts of products depend on their stabilities, and the reaction is under thermodynamic control. E. None of the above.

22. Which of the following factors has no effect on the rate of SN1 reactions?

A. the nature of the alkyl halide.

B. the nature of the leaving group.

C. the concentration of the alkyl halide.

D. the concentration of the nucleophile.

E. the value of the rate constant.

23. Identify the pair of compounds:

A. identical

H CH3 H Cl B. conformational isomers C C C C C. constitutional isomers

BrCl BrCH3 D. configurational isomers

E. none of the above.

24. Choose the enantiomer of the compound below:

H

H3C CH2Cl

Cl

A. B. C. D. E.

CH2Cl CH3 Cl Cl H

H3C H ClH2C CH3

ClH HCl ClH2CH CH3 CH2Cl Cl

H3C ClH2C

25. Which of the following pairs are resonance structures?

I. CH3 CH3 II.CH3 III. CH3 CH3

and and

IV. CH3 V. CH3 CH3

and and

A. I.

B. II.

C. III.

D. IV.

E. V.

26. Provide an IUPAC name for the compound.

CH3 A. N,N,1,1-tetramethylethanamine

H3C C CH3 B. N,N-dimethyl-2-butanamine

C. N,N,2-trimethyl-1-propanamine

H3CCH3 D. N,N,2-trimethylpropanamine

E. N,N,2-trimethyl-2-propanamine

27. Consider the interaction of two hydrogen 1s atomic orbitals of the same phase. Which of the statements below is an incorrect description of this interaction?

A. A sigma bonding molecular orbital is formed.

B. The molecular orbital formed is lower in energy than a hydrogen 1s atomic orbital.

C. The molecular orbital formed has a node between the atoms.

D. The molecular orbital formed is cylindrically symmetrical.

E. A maximum of two electrons may occupy the molecular orbital formed.

28. Give the major product for the following E1 reaction:

29. Which is the strongest acid?

A. O B. Cl O C. Cl O D. Cl O E. Cl O

Cl

OHOHOHOHOH

ClCl Cl Cl

Cl

30. Identify the compound with the highest pKa:

A. CH3NH2

B. CH3OH

C. CH3COOH

D. H2O

E. CH3NH3+

31. What is/are the product(s) of the following reaction?

HBr H2C C CHCH3 H

H2C C C CH2 H Br H3C CBr CBrHCH3 H2CBr HC CH CH3 H H

I. II. III.

A. I only.

B. II only.

C. III only.

D. I and II.

E. I and III.

32. Which of the following compounds will undergo SN2 reaction most readily?

A. (CH3)3CCH2I

B. (CH3)3CCl

C. (CH3)2CHI

D. (CH3)2CHCH2CH2CH2Cl

E. (CH3)2CHCH2CH2CH2I

33. What is the relationship between the two structures below?

A. enantiomers

B. diastereomers

C. configurational isomers

D. identical compounds

E. constitutional isomers

34. Which of the following is the staggered conformation for the rotation about the C1-C2 bond in the following structure?

CH3

CH3CHCH2CH3

1 2 3 4

A. H B. CH3 C. H D. H E. H

H3CCH2CH3 H3CCH2CH3 H3CCH3 C2H5H

H

HH H3CH HH HH H3CC2H5 H H H H H

35. What reagents can best be used to accomplish the following transformation?

OH

A. 1. BH3 2. HO-, H2O2

B. H+, H2O

C. 1. Hg(OAc)2, H2O/THF 2. NaBH4

D. Hg(O2CCF3)2, CH3OH 2. NaBH4

E. NaOH, H2O

36. What mechanism predominates in the reaction below?

CH

CH2CH3 3OH, heat

Cl

A. SN2

B. SN1 without rearrangement

C. SN1 with rearrangment

D. E2

E. E1

37. What is the IUPAC name for the following compound?

A. 5-methylcyclohexene

B. 4-methylcyclohexene

H3CC. 1-methyl-3-cyclohexene

D. 1-methyl-4-cyclohexene

E. methylcyclohexene

38. Assuming no other changes, what is the effect of doubling only the concentration of the alkyl halide in an SN2 reaction?

A. no change.

B. doubles the rate.

C. triples the rate.

D. quadruples the rate.

E. rate is halved.

39. Which of the following has two equatorial alkyl substituents in the most stable conformation?

A. 1,1-dimethylcyclohexane

B. cis-1,2-dimethylcyclohexane

C. cis-1,3-diethylcyclohexane

D. cis-1,4-diethylcyclohexane

E. trans-1,3-diethylcyclohexane

40. Which of the following alkyl halides gives the fastest SN1 reaction?

A. Br B. C. D. E.

Br Br

Cl

Cl

41. Which of the following alkenes yield 3-bromo-3-methylpentane as the major product upon addition of HBr?

I. II. III. IV.

A. I and II only.

B. III only.

C. I, II, and III only.

D. All of them.

E. None of them.

42. Which of the following statements about propene, CH3CH=CH2, is correct?

A. All nine atoms lie in the same plane.

B. The compound has a cis and trans isomer.

C. It generally acts as a Lewis acid.

D. There is a total eight sigma bonds.

E. All the carbon atoms are sp2 hybridized.

43. Which of the following is the most stable carbocation?

A. B. C. D. E.

CH3 CH3 CH3 CH22

44. Which of the following statements is incorrect about benzene?

A. All of the carbon atoms are sp hybridized.

B. It has delocalized electrons.

C. The carbon-carbon bond lengths are all the same.

D. The carbon-hydrogen bond lengths are all the same.

E. All twelve atoms lie in the same plane.

45. Which of the following carbocations is likely to rearrange?

H3C CH3 H3C CH3 H3C CH3 H3C 2

I. II. III. IV.

A. I.

B. II.

C. III.

D. IV.

E. II and IV.

46. What is the activation energy for the reaction B --> A in the following diagram?

A. A

B. B

C. C

D. D

E. E

47. Which of the following groups has the highest priority in the Cahn-Ingold-Prelog rules?

A. O B. O C. D. E. O

OH OCH3 OHH O

48. Give the best product for the reaction below:

2. CH3CH2Br

A. B. C. D.

49. Name the structure:

A. (Z)-4,5-dimethyl-4-hepten-1-ol

H3CCH2CH2CH2OH B. (E)-4,5-dimethyl-4-hepten-1-ol

C. (E)-3,4-dimethyl-3-hepten-7-ol

H3CH2C CH3 D. (Z)-3,4-dimethyl-3-hepten-7-ol

E. (E)-4,5-dimethyl-4-heptenol

50. Give the major product of the following E2 elimination.

A. B. C. D. E.

Your book describes a treatment for -Thalassemia, a disease where the body cannot make the form of hemoglobin. Transfusions are necessary to provide the body with external sources ofhemoglobin but that procedure causes a potentially fatal buildup of Fe in the bofy. To eliminate Fe2+, desferrioxamine B (DB) is given to patients. DB is a chelating agent for Fe2+ that has three hydroxamate groups which complex with the Fe or H. The hydroxamate group in its uncomplexed basic form is

   O- O

    |   ||

R-N-C-R’

In this formula, R and R’ stand for other carbon-containing parts. When dB is administered to patients, it chelates with the Fe2+ in three spots forming a Fe2+-DB complex with a formation constant of 5 x 1030. The Fe2+-DB complex can then be excreted from the body.

a) Assume the body has a blood volume of 4.8 liters, the concentration of Fe2+ in the blood is 3.6 x 10-5 M, and the blood pH is 7.1. Assume that 200 mgm of DB is administered to a patient (DB has a molecular weight of 555) and the DB goes completely into the patient’s blood system. Determine the concentration of uncomplexed Fe that remains after the administration. The acid dissociation constants for DB are

K1 = 5 x 10-5

K2 = 6 x 10-6

K3 = 8 x 10-8

b) How many grams of Fe2+ will be removed from the patient’s body if all the Fe2+ - D is excreted? (atomic weight of Fe = 55)

c) If the number of grams determined in part b) are removed each day, how many days will it take to remove the 4 grams of iron that typically accumulate in a person’s body over 1 year?