CHEM151

More problems for Exam 3

More problems for Exam 3


1. Write the formulas for the following pairs of atoms: Rb and N, Ba and S,
Cs and I, Al and O, Ga and P, Al and N

Which of the above bonds is the strongest? weakest? Explain.

2. Write the Lewis structures, predict the shape and indicate the bond angles for the
following: NO2-1, O3, CO2 , H2Se, CBr4, CO
Which molecules are polar? Show any resonance structures.

3. Which of the following bonds is the most polar? the least polar? Classify using
the “line” diagram.
Br-Cl, H-F, N-F, K-Cl

4. Which compound has the strongest bond in the following pairs. Explain.

KCl and LiF BaS and AlN

Exam 3 Problems

Problem Session
Chemistry I, Exam III

1. Write the formulas for the following pairs of atoms: K and O, Na and N,
Cs and Br, Al and S (Hint: These are metal-nonmetal compounds)

2. Write the Lewis structures for the following: H2O, NO2-1, O3, NF3,
CO3- 1 Any resonance structures?

3. Which of the following bonds is the most polar? the least polar? Classify using
the “line” diagram. (See electronegitivity table from class)
Br-I, H-F, C-O, K-F

4. Predict the shape and indicate the bond angles for the following molecules and
ions: ClI3, SO4-2, H2S, NO3-1, O3


5. Which compound has the strongest bond in the following pairs. Explain.
KI and NaCl MgO and AlN

MASSASOIT COMMUNITY COLLEGE
CHEMISTRY I (CHEM151)
Fall 2012
SYLLABUS

Course Description: This course in general chemistry is designed for those students who plan to continue in science or a science related area. The structure of the atom, modern chemical bonding, stoichiometry, states of matter. kinetic theory, gas laws, and solutions are the major topics covered. Lecture: 3 hours. Labratory: 2 hours.
Prerequisite: High school algebra or equivalent or instructor’s approval.

Instructor: Professor Robert A. Demers
Office: Brockton: S541, Telephone ex. 1656
e-mail: [email protected]

Text: Burdge, Chemistry, McGraw Hill, 1st or 2nd Edition (Recommended)
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Chapter 1 The semester begins with discussions of the classification of matter, the metric system, accuracy and precision, significant figures, dimensional analysis and heat and temperature.

Chapters 2,3,4 A brief discussion of Dalton's Atomic Theory and some of the Laws of Chemistry lead to the considerations of atomic numbers and molecular weight, the mole concept, per-cent composition problems, mass-mole problems, limiting reagent problems and a brief discussion of solutions and the various units of concentrations.

Chapters 6 This section develops the structure of the atom from its simplest descriptions to the modern-day view. Included are the topics of sub-atomic particles, electromagnetic energy, the Bohr Model of the atom, the work of deBroglie and Heisenberg, wave mechanics, quantum numbers, orbitals and orbital filling and trends within the perodic table.

Chapters 7,8,9 These chapters deal with the various approaches to chemical bonding. Included are the topics of the octet rule, ionic and covalent bonding, polar covalent bonding, VSEPR theory, valence bond theory, and if possible, molecular orbital theory.

Chapter 11 This chapter covers the gaseous state. The focus of the material will be on the various gas laws; Boyle's Law, Charles' Law, Avogadro's Law the Ideal Gas Law, Graham's Law and the Kinetic Molecular Theory of Gases.

Course Policys

CHEM 151, Sections 01 and 61, General Chemistry L

Professor Robert A. Demers
[email protected]

Two areas that sometimes cause confusion in a new course are testing and grading. Hopefully, this document will help to eliminate any problems in these two areas.

My grading assignments are as follows:

94.0 - 100 = A
89.5 - 93.9 = A-
86.3 - 89.4 = B+
82.9 - 86.2 = B
79.5 - 82.8 = B-
76.3 - 79.4 = C+
72.9 - 76.2 = C
69.5 - 72.8 = C-
66.3 - 69.4 = D+
62.9 - 66.2 = D
59.5 - 62.8 = D-
Below 59.5 = F

During the semester there will be a total of five (5) exams, four (4) hour exams plus a comprehensive final. There are no make-up exams during the semester. (A missed exam can be made up if need be, during a make-up period at the end of the semester before the final exam). The class part of your overall grade (70%) will be determined as follows: After dropping the lowest hour exam grade, the final exam will be counted once and will then replace any remaining hour exam that it exceeds. The average of these four (4) grades will be your class grade. The laboratory part of your grade will count 30%. Laboratory grading will be discussed during the first lab. If you have an “A” average based on the 4 hour exams, you will be excused from the final exam.

The basic structure of the course is a lecture/lab format. I can not stress enough the importance of keeping up with the work as we go along. While I do not formally keep attendance, I consider you to be adults and simply expect that you will attend each class. (Attendance in this course tends to be self-policing). Please feel free to come in for help if you feel that you are falling behind -- or for that matter, just to chat. My office in Brockton is in Room S-541; telephone, 1656. In Canton my office is Room 322, telephone extension, 2134. It is best to contact me by e-mail.

Cell phone policy: Out of common courtesy, please put your cell phone on “silent” mode during class and please complete your text messaging before you come to class. During exams, cell phones will not be allowed to be used as a calculator and must to be out of sight.

The tentative dates (+/- one class) for the exams are: 10/2, 11/23 , 11/13, 12/11, Final TBA

Wishing you a successful semester,

Professor Robert A. Demers

CHEM151@massasoit I would like to welcome you to my General Chemistry I class and I wish you success in the course. As I will say in class, the best thing you can do to ensure that success is to "show up". Don't be afraid to ask me for help. I will do my best to get you through the course, hopefully without too much "kicking and screaming" ;-) Also, please do not attempt to "Friend" me. Do not take this personally, but I do not want to be your "Friend" and you do not want me to be your "Friend". For example, you do not want me to know that you were out partying the night before an exam. ;-) Our relationship must be a professional one.

Text book and Lab manual for General Chemistry I

While a text book is not required for the course I STRONGLY recommend that you get one. The book for the course is Chemistry by Julia Burdge, 2nd Edition. The book new is very expensive ($200+) so I would urge that you rent it from one of the many college book rental sites on line. The cost for the semester should be under $60. The lab manual (Chemistry, A Laboratory Manual by Kendra Twomey, one of the Massasoit chemistry professors) IS REQUIRED and can be purchased from the Massasoit bookstore.

Calculator for the Chem I Course: You will need to get a Scientific Calculator ASAP. If you do not already have one, the Casio fx-260 Solar is a great buy at around $10.