# Chem Final Review

Topics: Chemical bond, Electron, Molecular geometry Pages: 2 (351 words) Published: February 2, 2012
Help Room 1-3 Mon GMCS 212
2-4 Thu
Final Exam Sat 6-8 pm
Room assignments to be determined
Alternate times, email chem200@sciences.sdsu.edu

FINAL EXAM
* problems 1-10 exam 1 material
* probelsm 11-20 exam 2 material
* problems 21-30 exam 3 material
* problems 31-35 new material (MO theory from ch 11, ch 12) All Single-choice 10 multiple choice material

2. Which pair of atoms/ions has same # of electrons?
32p and 32s15e 16e-
Al 3+ and Cl-10e-18e-
Xe and I-54e-54e-
13C 14N6e- 7e-

^ the 13 on C is mass number. = # protons + # neutrons.

3. N2 + 2 O2 + Cl2 -> 2 NO2

Start with 6 mol N2, 4 mol O2, 4 mol Cl2, Find limiting reagent and amounts remaining of excess reactants

N2 + 2 O2 + Cl 2
6 mol 4 mol 4 molstart
Max yield x (2mol No,Cl/ 1 mol N2)
Of No2Cl = 12 mol 4 mol 8 mol
O2 is the limiting reagent. 4 mol of NO2Cl
(4 mol NO2Cl) (1 mol N2 / 2mol No2Cl) = 2 mol N2 consumed

6 mol N2 – 2 mol N2 = 4 mol N2 left
^at start^ used up

(4 mol NO2Cl) (1 mol Cl2/2mol NO2Cl) = 2 mol Cl2 consumed
4 mol Cl2 – 2 mol Cl2 = 2 mol Cl2 left
^at start^used up

4. What is energy of a 4p electron in Li^2+ ?

E electron = -2.18 x 10^-18 J (Z^2 / n^2) Z = at. No.n=princ. Quantum# For 1-electron atom

E = -2.18 X 10^-18 J (3^2 / 4^2) = -1.23 x 10^-18 J
5. Which of the following is not a good resonance structure?

6. How many sigma and pi bonds are in cyanogen
:N TripleBOND C – C TRIPLEBOND N:
3 sigma bonds and 4 pi bonds

7. What is the only allowed value of l if n = 3 and ml = -2?
l=2
8. Which bond angle in acetone has a value of 120 degrees?
Lewis structure
C-C-C is ~ 120 degrees
Trigonal planar , ~120 degree angles.