Humboldt State University ® Department of Chemistry

Richard A. Paselk

Chem 110

Chem 110, Dr. Paselk	Final Exam	Name
Fall 2002	(200 pts)	Lab

Part I (70 pts): Circle the correct answer for each of the following questions (two points each).

1. The formula of Trifluorotriaquavanadium(III) is:

a. VF₃(H₂O)₃ b. VF₃(H₂O)₃³⁺ c. VF₃(H₂O)₃^3- d. VF₃(H₂O)₃^- e. none of these

2. The correct name of the AgBr₂^- ion is:

a. dibromosilver(II) b. dibromoargentate(II)

c. dibromosilver(I) d. dibromoargentate(I)

e. none of these

3. The correct name of the CrOF₄^- ion is:

a. oxotetrafluorochromate(V) b. tetrafluorooxochromate(V) c. oxotetrafluorochromium(VII) d. tetrafluorooxochromate(III) e. tetrafluorooxochromium(V)

4. The ejection of an electron during radioactive decay is called:

a. a decay b. positron emission c. b decay d. fission e. K capture

5. Which one of the following pairs of ions would you NOT expect to find together in acidic solution:

a. C₂H₃O₂^-, ClO₃^- b. ClO₃^-, I^- c. NO₃^-, HSO₄^- d. Cl^-, Br^- e. none of these

6. The hybridization of carbon in acetylene (C ₂H₂) is:

a. sp b. sp² c. sp³ d. dsp³ e. none of these

7. Which of the following processes produces an isotope with a decrease in atomic number?

a. a decay b. positron emission c. b decay d. fusion e. none of these

8. In a low spin complex the electrons in the metal’s 3d orbitals:

a. are all paired b. are all unpaired

c. populate the hybridized 3d orbitals as if they were degenerate (same energy)

d. populate the lower energy hybridized 3d orbitals first

e. none of these

9. A bidentate ligand is an example of:

a. two anions bound to a single metal cation

b. two metal cations bound to a single anion

c. a single anion bonded with two bonds to a metal cation

d. a single metal cation bonded with two bonds to an anion

e. none of these

10. What is the oxidation number of X in MgXO4?

a. +4 b. +7 c. +8 d. +10 e. none of these

11. In V(H₂O)₆³⁺ the hybridization of vanadium is:

a. dsp³ b. d²sp² c. sp³ d. d²sp³ e. none of these

12. The hybridization of phosphorus in PCl₅ is:

a. dsp³ b. d²sp² c. sp³ d. d²sp³ e. none of these

13. The geometry of a molecule of CH₂O can be described as:

a. square planar b. trigonal planar c. tetrahedral d. octahedral e. none of these

14. a particles, b particles and g rays are different types of:

a. beta particles b. radio waves c. nucleons d. ionizing radiation e. none of these

15. The inert pair effect predicts that lead will have a stable oxidation state of :

a +4 b. +3 c. +5 d. +2 e. none of these

16. The most stable oxidation state of arsenic is:

a +3 b. -3 c. -5 d. 2 e. none of these

17. Which of the following will form the strongest basic oxide?

a. Al b. Zn c. Mg d. Sn e. Ca

18. Which of the following oxoacids is the strongest?

a. HOCl b. HOClO c. HOBr d. HOClO₃ e. HOClO₂

19. Which of the following elements forms the most acidic oxide:

a. Al b. P c. Mg d. Si e. Cl

20. Which of the following elements exhibits the highest oxidation number?

a. Co b. Cr c. Fe d. Mn e. Ni

21. Which of the following elements does not exhibit a stable oxidation number of +2?

a. Ci b. Sc c. Fe d. Zn e. none of these

22. Which of the following elements is the most metallic?

a. N b. Ge c. Sn d. Pb e. As

23. Which of the following elements forms three-center bonds?

a. N b. B c. Sn d. C e. P

24. Which of the following elements does not form stable multiple bonds?

a. N b. S c. O d. C e. none of these

25. Pressure is:

a. an irreversible property b. an extensive property c. a reversible property d. an intensive property e. none of these

26. A Faraday is the:

a. the charge on an proton

b. the amount of current required to plate one mole of Zinc

c. the charge carried by a mole of electrons

d. number of electrons per mole of carbon

e. none of these

27. What happens to the cell potential as a battery charges?

a. it decreases b. it changes from positive to negative c. it remains constant d. it increases e. none of these

28. A sample that is diamagnetic

a. will be repelled by an electric field

b. will be attracted into a magnetc field

c. will be attracted into an electric field

d. will be repelled by a magnetic field

e. none of these

29. p_z-orbitals on two adjacent bonded atoms can form:

a. s bonds b. p bonds c. part of a delocalized electron p system d. all of these e. none of these

30. Which of the following has the smallest buffer capacity:

a. 0.01 M acetic acid / 0.01 M sodium acetate

b. 0.1 M acetic acid / 0.1 M sodium acetate

c. 1.0 M acetic acid / 1.0 M sodium acetate

d. all have the same buffer capacity

e. none of the above

31. Non-metals are:

a. good conductors of heat b. brittle c. ductile d. all of these e. none of these

32. The arrangement of the hybrid orbitals formed by a dsp³ transition metal is:

a. tetrahedral b. square planar c. octahedral d. trigonal bipyrimidal e. none of these

33. Radioactive decay obeys

a. zero order kinetics b. first order kinetics c. second order kinetics d. third order kinetics e. none of these

34. Weak field ligands tend to absorb visible light:

nearer the red end of the visible spectrum

in the microwave spectrum

nearer the violet end of the visible spectrum

nearer the center of the visible spectrum

none of these

35. The relative speeds of alpha, beta and gamma particles follows which of these trends:

a. a <b <g b. a >b >g c. b <a <g d. a <g <b e. none of these

Part II (30 pts): Circle the correct answer for each of the following (five points each).

1. Which of the ions below would exhibit the greatest paramagnetism when complexed to a weak field ligand?

a. Fe⁺³ b. Fe⁺² c. Co⁺² d. Cu⁺² e. Mn⁺⁴

2. In a decay series starting with ²⁴¹₉₄Pu a total of 8 alpha particles and five beta particles are emitted. What is the final nuclide formed in this series?

a. ²²⁵₉₉Es b. ²⁰⁹₈₃Bi c. ²⁰⁹₈₂Pb d. ²²¹₉₂U e. ²⁰⁹₉₉Es

3. The rate constant for the alpha decay of Thorium 230 is 8.7 x 10^-6 y^-1. What is t_1/2 for this isotope?

a. 1.3 x 10^-5y b. 6.5 x 10⁵ y c. 4.0 x 10⁴ y d. 8.0 x 10⁴ y e. none of these.

4. Which of the following complex ions would absorb color of the shortest wavelength

a. FeCl₆^3- b. Fe(NH₃)₆³⁺ c. Fe(OH)₆^3- d. Fe(H₂O)₆³⁺ e. Fe(CN)₆^3-

5. In a fission reaction the mass of the resulting nuclei and particles is 2.056 amu less than the mass of the parent nuclei, How many joules of energy are released per mole?

a. 1.401x10¹² b. 1.737x10¹³ c. 1.848x10¹⁴ d. 6.163x10⁵ e. none of these

6. Which of the following materials is best to prepare a buffer with a pH of 6.5?

a. H₂S / NaSH K_a= 1.0 x 10^-7 b. HOCl / NaOCl K_a= 3.5 x 10^-8 c. HC₃H₅O₂ / Na C₃H₅O₂ K_a= 1.3 x 10^-5

Part III ( 40 pts) Write NET ionic equation(s) for the reaction(s) which occur(s) when the following are mixed. (If there is no reaction, indicate by "NR." )

1. Sodium carbonate is added to a dilute solution of calcium chloride.

2. Potassium thiocyanate is added to a solution of a single cation, turning it deep red.

3. Ammonium thiocyanate is added to a dilute solution of cobalt chloride.

4. Sodium hypochlorite is added to a basic solution of chromium(III) chloride.

5. Sodium hydroxide is added to zinc chloride solution forming a precipitate.

6. Additional sodium hydroxide is added to the precipitate of (e), dissolving it.

7. Sulfur trioxide is added to water.

8. Sodium sulfide is added to a solution of stannic chloride.

9. hydrochloric acid is added to a solution of mercurous nitrate.

10. Aluminum metal is added to tin(IV) dissolved in 6M hydrochloric acid (SnCl₆^2-).

Part IV (64 pts) Complete the the work requested in the following questions and problems (point values given for each)

(15) 1. Fill in the blanks with the correct symbol for the nuclide involved, including chemical symbol, atomic number and mass number. No partial credit for these will be given.

(a) ________ Æ ²³⁴₉₀Th + a

(b) ²¹⁰₈₃Bi Æ ________ + b

(c) ⁵⁹₂₇Co + ¹₀n Æ Æ _______ + a + b

(d) ²³⁵₉₂U + ¹₀n Æ ⁹⁴₃₈Sr + ________ + 3¹₀n

(e) ³₁H + ²₁H Æ ________ + ¹₀n

(10) 2. After 8.646 years 65.00% of a sample of the inert gas nuclide ²²²₈₆Rn has spontaneously decayed. What is the half-life of this nuclide?

(10) 3. Calculate the [Cu²⁺] in a solution prepared by dissolving 0.050 mol of copper(II) nitrate in 1.00 L of 1.00M ammonia (assume no volume change). For the copper ammonia complex ion K_diss = 1.0 x 10^-12; K_b = 1.8 x 10^-5 for ammonia. SHOW WORK FOR CREDIT!

(10) 4. For the reaction

the value for D G° is —374 J/K· mole. Find the value of D H°_f for SF_6(g) given that:

a. for F_2(g) S° = 203 J/mol

b. for SF_6(g) S° = 292 J/mol and

c. for SF_4(g) D G°_f = -731 kJ/mol

SHOW WORK FOR CREDIT!

(10) 5. Consider the manganese(II) ion. The hexaaqua complex of this ion is a pale pink while the hexacyano complex is intense violet.

a. Explain the difference in the intensity of the color of these two complexes. Include properly labeled orbital diagrams to illustrate your argument.

 

b. Do these complexes differ in paramagnetism? If so explain why.

(9) 6. Explain the following:

a. The properties of the second and third rows of the transition metals are more similar to each other than those of the first and second rows.

 

b. Metal ions with a coordination number of six can have four geometrical isomers.

 

c. Iron, nickel and gold exhibit vastly different corrosion properties.

 

© R A Paselk

Last modified 8 December 2006