# Chem Final Review

**Topics:**Chemical bond, Electron, Molecular geometry

**Pages:**2 (351 words)

**Published:**February 2, 2012

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.

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