Chemistry 2202 Test - U2 s3 and s4 Page 3 of 5
Chemistry 2202
Test #2 version 2 - 2006
U2 s3 and s4
Part A: Multiple choice. Place the best answer for each of the following on the answer sheet on page 4 of this test.
1. What determines the central atom of a molecule?
a) electronegativity
b) number of bonding electrons
c) number of lone pairs
d) period number
2. Which structural diagram is correct?
a) b) c) d)
3. The VSEPR theory says that the shape of a molecule is determined by repulsions of which elelctrons?
a) bonded pairs
b) lone pairs
c) lone pairs and bonded pairs
d) unbonded electrons
4. Which molecule is trigonal planar?
a) b) c) d)
5. What is the shape around the central atom that has one lone pair and forms covalent bonds with three chlorine atoms?
a) bent
b) tetrahedral
c) pyramidal
d) trigonal planar
6. What is the shape around the central atom in the PBr3 molecule?
a) planar
b) pyramidal
c) tetrahedral
d) V-shaped or bent
7. Which molecule has a trigonal planar shape around the central atom(s)?
a) C2H4
b) NF3
c) OCl2
d) SiF4
8. In which diagram is the bond dipole correctly illustrated?
a) b) c) d)
9. In which pair do both molecules have a molecular dipole?
a) CCl4, CH3Cl
b) H2O, CO2
c) NH3, CCl4
d) NH3, H2S
10. Which is an intramolecular force?
a) covalent bond
b) dipole – dipole
c) hydrogen bond
d) London dispersion force
11. What determines the strength of London dispersion forces?
a) electronegativity
b) hydrogen bonded to F, O, or N
c) number of electrons and molecule structure
d) polarity
12. Which molecule is isoelectronic with H2O?
a) Cl2
b) He
c) NH3
d) O2
13. Which molecular substance has the strongest London Dispersion Forces?
a) CH3CH2OH
b) C6H6
c) PI3
d) SiO2
14. Which substance has both London dispersion and dipole-dipole forces, but does not have hydrogen bonding?
a) CH3OH
b) CH3F
c) Cu
d) SiO2
15. Which substance is a liquid at room temperature?
a) CCl4
b) Ga
c) Na3N
d) SiO2
16. Which observation is explained by surface tension?
a) An eleastic band warms up as it is stretched.
b) Pancake syrup gets very thick when placed in the refrigorator.
c) Water gathers in raised drops on the surface of waxed vehicles.
d) Your hands warm up as you gently rub them together.
17. Which substance will be most soluble in water?
a) / / b) /c) / / d) /
18. What intermolecular forces are present the liquid CH3F ?
a) dipole-dipole and London dispersion
b) dipole-dipole, Hydrogen bonding, and covalent bonding
c) dipole-dipole, London dispersion, and covalent bonding
d) dipole-dipole, London dispersion, Hydrogen bonding, and covalent bonding
19. Which substance would be expected to have the highest melting point?
a) C3H7OH
b) C25H52
c) CO2
d) ZnFe
20. Which liquid should have the highest viscosity?
a) methanol, CH3OH
b) butanol, C4H9OH
c) octanol, C8H17OH
d) duodecanol, C12H25OH
Chemistry 2202 Test - U2 s3 and s4 Page 4 of 5
Name:______Site:______Page:___of___
Chemistry 2202
U2 s3 and s4 - 2006
Answer Sheet
{20} Part A: Multiple Choice.
Chemistry 2202 Test - U2 s3 and s4 Page 4 of 5
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Chemistry 2202 Test - U2 s3 and s4 Page 4 of 5
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Part B: Place answers to the following questions in the space provided.
{12} 21. For each substance,
i) indicate the bond type
ii) list the significant force (or forces) of attraction that holds the substance together in the state indicated. Include a brief description of why these forces are present.
Bond type / Forces present (include all significant forces that apply)Au (s)
KCl (s)
F2 (g)
CH3Cl (l)
SiC(s)
C2H5OH(l)
{12} 21. Draw a Lewis diagram, a shape diagram , give the name of the shape, and then indicate the molecules poalrity.
CF2S / AsF3 / Si2Cl2Lewis Diagram
Shape Diagram
Shape Name
Polarity
(polar / nonpolar)
(if polar indicate this by drawing dipole arrows on the shape diagram)
{3} 22. Predict which compound will boil at a higher temperature by comparing the intermolecular forces present in CH3CH2OH, and CH3CH2CH3 .
{3} 23. Would you expect water and carbon tetrachloride to be miscible? Explain.