Oganic Lab

Only available on StudyMode
  • Download(s) : 127
  • Published : September 26, 2012
Open Document
Text Preview
Chemistry 1211 Prof. Dan Schwartz

Exam #2

Thursday, 3/13/2003 7:00 – 8:30 P.M.

There is a single correct choice for each question. Answer all questions on the Scantron sheet by filling in the proper bubble with a #2 pencil. If you change an answer, erase the undesired mark thoroughly. Be sure to fill in the boxes for your student number, name and lab section; then correctly fill in the corresponding bubbles beneath them. A periodic table and other useful information are attached to the back of the exam. There are 4 exam pages and 26 questions. Check to be sure you have answered them all! 1. (zero points) Which version of the exam do you have? (a) A (b) B

2. (5 points) Which two ions have the same electron configuration in the ground state? (a) Rb+ and Cs+ (b) Ba2+ and I– (c) Se2– and I– (d) Fe2+ and Fe3+

3. (5 points) List the elements Na, Ca, Rb, Cl, He in order of decreasing first ionization energy. (a) He > Cl > Ca > Na > Rb (b) He > Na > Ca > Cl > Rb (c) He > Na > Cl > Ca > Rb (d) Rb > Ca > Cl > Na > He

4. (5 points) Which ionic compound would be expected to have the highest lattice energy? (a) NaCl (b) MgO (c) AlF3 (d) Al2O3

5. (5 points) Which element, indicated by letter on the periodic table below, has a 2+ ion with electron configuration [Ar]3d10 ? (a) A (b) B (c) C (d) D

Exam #2

Page 1

6. (5 points) Element A has an electronegativity of 0.8 and element B has an electronegativity of 3.0. Which statement best describes the bonding in A3B? (a) The AB bond is largely covalent with a d– charge on A. (b) The AB bond is largely covalent with a d+ charge on A. (c) The AB bond is largely ionic with A as the cation. (d) The AB bond is largely ionic with A as the anion.

7. (5 points) Which is the most acceptable electron dot structure for N2H2? .. .. (a) H—N—N—H .. .. .. .. (b) H—N N—H (c) H—N N—H .. .. (d) H—N N—H

8. (5 points) Given that the electronegativity is 2.5 for both C and S, which is the best electron dot structure for SCN– based on formal charge? .. .. (a) [ : N C S :]– .. – (b) [ : N C S :] .. .. .. – (c) [ : N S C :] .. – (d) [ : N C S :] ..

9. (5 points) The following ball-and-stick molecular model is a representation of the amino acid alanine. Unshaded spheres = H. Choose the answer that best fills in the blanks in the following sentence: The carbon atom labeled C2 has a hybridization of hybridization of . (a) sp, sp2 (b) sp2, sp3 (c) sp3, sp2 (d) sp3, sp and the carbon atom labeled C3 has a

Exam #2

Page 2

10. (5 points) What is the shape of AsCl3? (a) T-shaped (b) tetrahedral (c) trigonal planar (d) trigonal pyramidal

11. (5 points) Which of the following is NOT a state function? (a) altitude (b) heat (c) internal energy (d) entropy

12. (5 points) For the reaction (a) DH0vap = –62.4 kJ/mol (b) DH0vap = 62.4 kJ/mol (c) DH0sub = –62.4 kJ/mol (d) DH0sub = 62.4 kJ/mol

I2(g) ‡ I2(s) , DH0 = –62.4 kJ at 25 ˚C. Based on these data, at 25 ˚C

13. (5 points) When 1.50 g of Ba metal is added to 100. g of water in a container open to the atmosphere, the reaction Ba (s) + 2 H2O (l) ‡ Ba(OH)2 (aq) + H2 (g) occurs and the temperature of the water rises from 22.0 ˚C to 33.1 ˚C. Given that the specific heat of water is 4.18 J/(g⋅˚C), find DH for the reaction. (a) –425 kJ (b) –3.09 kJ (c) 3.09 kJ (d) 425 kJ

14. (5 points) Find DH for the reaction BaCO3 (s) ‡ BaO (s) + CO2 (g) given 2 Ba (s) + O2 (g) ‡ 2 BaO (s) Ba (s) + CO2 (g) + 1/2 O2 (g) ‡ BaCO3 (g) (a) –1929.5 kJ (b) –1376.0 kJ (c) –284 kJ DH = –1107.0 kJ DH = –822.5 kJ (d) 269.0 kJ

15. (5 points) The figure below represents the spontaneous evaporation of isopropyl alcohol, (CH3)2CHOH. What are the signs ( + or –) of DH, DS, and DG for this process? (a) (b) (c) (d) DH = +, DS = +, DG = + DH = +, DS = +, DG = – DH = –, DS = –, DG = + DH = –, DS = –, DG = –

Exam #2

Page 3

16. (5 points) A basketball is inflated to a pressure of 1.50 atm in a 20.0 ˚C garage. What is the pressure of the basketball...
tracking img