SBVC CHEM 101 Dr. Lemieux
Name:______________________________________________
CHEMISTRY 101 Practice Exam #3
#1: Multiple Choice __________/ 60
#2: Free Response __________/ 40
TOTAL: __________/100
Instructions:
1. Cell phones must be put away and bags put on the floor.
2. Once we begin the exam, you must ask Dr. Lemieux if you wish to leave and return.
3. Anyone caught cheating in any fashion will be disciplined, as indicated in the syllabus.
Chem 101, Exam 3
Multiple Choice Section (3 points each, 60 points total)
1. Which of the following is the strongest intermolecular force assuming molecules of similar size?
A) dipole-dipole B) London dispersion C) hydrogen bond
D) they are all about the same
2. In which of the following substances would dipole-dipole interactions be the predominant intermolecular force?
A) Ar B) CO C) CH4 D) I2
3. Particles in a suspension are
A) small enough that they do not scatter light.
B) small enough that they do not settle out under the influence of gravity. C) large enough that they cannot pass through filter paper.
D) more than one correct response E) no correct response
4. Which of the following molecular compounds has at least one double bond? A) N2
B) CH3OH C) CCl4 D) H2S
5. A colloidal dispersion differs from a true solution in that solution particles A) tend to settle at an appreciable rate.
B) are large enough to scatter light.
6. What is the molarity of the solution prepared by diluting 40.0 mL of 12.0M NaOH to a final volume of 160.0mL?
A) 3.00 M B) 4.00 M C) 8.00 M D) 36.0 M
7. Which of the following ionic compounds is insoluble in water? A) Na3PO4
B) CaCl2 C) Mg(OH)2
D) more than one correct response E) no correct response
8. Which of the following statements is correct?
A) Dipole-dipole interactions occur only between nonpolar molecules. B) A hydrogen bond is a particularly strong London dispersion force. C) London forces are the strongest intermolecular force between small polar
molecules
D) Hydrogen bonding occurs in substances in which hydrogen is bonded to an atom with high electronegativity.
9. Which of the following substances is soluble in water? A) NH3
B) CH4 C) CaCO3
D) more than one correct response E) no correct response
10. The bonding of metal atoms can be described as A) atoms held by strong hydrogen bonds
B) positive nuclei held by relatively mobile electrons C) electrons shared in covalent bonds
11. If two starch solutions, A and B, are separated by a semipermeable membrane. Solutions A and B and be have concentrations 0.80M and 0.40M, respectively. During osmosis there is a net flow of
A) starch molecules from solution A to solution B B) starch molecules from solution B to solution A C) water molecules from solution A to solution B D) water molecules from solution B to solution A
12. Which of the following substances has the strongest London dispersion forces? A) CH4
B) C3H8 C) C6H14
D) all of the above have the same forces
13. What is the molarity of the solution prepared dissolving 15.0 g of NaCl in water to make 2.0 L of solution?
A) 3.00 M B) 4.00 M C) 8.00 M
D) none of the above
14. Which state of matter are ionic compounds generally in at room temperature? A) solid
B) liqiid C) gas
D) liquid or gas E) none of the above
15. Which of the following compounds contains only covalent bonds? A) NF3
B) AgCl C) NaCN
16. Given the following electronegativites: Na = 0.9, H = 2.1, Cl = 3.2 which of the following statements is true?
A) HCl is a nonpolar covalent compound and Cl2 is a polar covalent molecule B) NaCl is a nonpolar covalent compound and HCl is an ionic compound C) Cl2 is a nonpolar covalent molecule and HCl is a polar covalent molecule D) H2, Cl2, and HCl are nonpolar covalent molecules
17. Electronegativity is a concept that is useful along with other concepts in A) formulating a statement of the octet rule.
B) predicting the polarity of a bond.
C) determining the charge on a polyatomic ion.
D) deciding how many electrons are involved in a bond.
18. Which of the following statements concerning differences between ionic and molecular compounds is correct?
A) The electrons in covlent bonds are more equally shared between the bonded atoms than in ionic bonds.
B) Covalent compounds contain two elements, and ionic compounds contain three or more elements.
C) Ionic compounds contain oxygen, and molecular compounds do not. D) no correct response
E) more than one correct response
19. Which of the following molecular compounds has a triple bond? A) HCN
B) CH2O C) CS2 D) H2O
20. What glassware is used to produce solutions accurately? A) erlenmeyer flask
B) volumetric beaker C) buret
Name________________________ Student ID #__________________________
Free Answer Section (40 points total)
Important: You must show ALL work to receive full credit. Remember to keep track of your sig figs. Write your answer with units in the box.
21)Draw the Lewis structures for the following molecules. State the molecular geometry and whether or not the molecule is polar. (16 points)
a. SH2
b. CH4O
c. NBr3
22)Of the molecules above, which would be most soluble in water? Explain by discussing the intermolecular forces involved. (4 points)
Total valence e-: _____________
Geometry: __________________
Polar? yes or no
Total valence e-: _____________
Geometr C: __________________
Geometry O: _________________
Polar? yes or no
Total valence e-: _____________
Geometry: __________________
23)What volume of 5.00% (m/v) sucrose solution contains 280.0 mg sucrose? (7 points)
24)What is the (v/v)% concentration of a solution made by dissolving 150.0 mLethanol in water to make a 855 mL solution? (6 points)
Important Information
Electronegativites
