Houston Community College
Dr. Mohamed Elbaccouch
CHEM 1405
Spring 2015 - Test # 3
Answer the Following Questions.
Student Name: ______________________________
1. How many single bonds, double bonds, and lone pairs are on the central Carbon atom in the
correct dot structure of carbon dioxide, CO2?
A) 1 single, 1 double, 1 lone pair
B) 2 single, 1 double, 0 lone pairs
C) 0 single, 2 double, 0 lone pair
D) 0 single, 2 double, 1 lone pair
2. Which one of the following molecules has lone pairs on the central atom?
A) CCl3H
B) NH3
C) BF3
D) SF6
3. What is the molecular geometry, polarity, and bond angle of CH4?
A) Octahedral, Polar, 90o
B) Octahedral, Non-Polar, 90o
C) Tetrahedral, Polar, 109.5o
D) Tetrahedral, Non-Polar, 109.5o
4. Which of the following defines a lone pair of electrons?
A) Two electrons shared between atoms
B) Two electrons not involved in a bond
C) Two electrons transferred to an atom
D) Two electrons lost by an atom
5. Which of the following molecules has hydrogen bonding?
A) H2O
B) HCl
C) HBr
D) CH4
6. Which of the following statements is correct?
A) Valence Electrons are responsible for forming ionic bonds and covalent bonds.
B) Valence Electrons are found close to the nucleus.
C) The length of a covalent bond equals the sum of the atomic radii of the atoms.
D) Covalent bonds occur when an atom accepts or loses an electron.
7. Which of the following molecules has a resonance structure?
A) SO3
B) CH3OH
C) NH4+
D) C2H4
8. Which of the following is held together by ionic bonds?
A) AlCl3
B) Mg3N2
C) Cu2S
1
D) all of the above
9. CO2 is classified as which of the following?
A) Binary ionic
B) Ternary ionic
C) Binary molecular
D) Ternary molecular
10. How many valence electrons are in a bromine atom and a bromide ion?
A) 1 and 7, respectively
B) 1 and 8, respectively
C) 7 and 8, respectively
D) 7 and 10, respectively.
11. Which of the following ions has the electron configuration of [Ne]?
A) Mg
B)Mg2+
C) O
D)O2+
12. Given the electronegativity values H= 2.1, N = 3.0, O = 3.5, and P = 2.1,
which of the following molecules contains nonpolar covalent bonds?
A) water, H2O
B) Laughing gas, N2O
C) phosphine, PH3
D) ammonia, NH3
13. What is the most electronegative atom in the periodic table?
A) H
B) Fr
C) Li
D) F
14. What is the strongest intermolecular force in a liquid containing polar molecules?
A) Covalent bonding B) Cationic bonding C) Dipole forces
D) Dispersion forces
15. What are the products from the complete combustion of a hydrocarbon?
A) Carbon dioxide and water
B) Carbon monoxide and hydrogen
C) Carbon monoxide and water
D) Carbon dioxide and hydrogen
16. What is the systematic name for for Ca(NO3)2•4H2O?
A) Calcium nitrate dihydrate
B)Calcium nitrate tetrahydrate
C) Calcium nitrite dehydrate
D) Calcium nitrite tetrahydrate
17. Identify the type of bond and the strongest intermolecular force that occurs between Cl2
molecules?
A) Ionic, Dipole forces
B) Covalent, Dipole Forces
C) Ionic, Dispersion forces
D) Covalent, Dispersion Forces
18. Calculate the heat required to convert 20.0 g of ice at –20.0oC to liquid water at 50.0°C. The
specific heat of ice is 0.50 cal/(g°C), the heat of fusion for ice is 80.0 cal/g, and the specific heat
of water is 1.00 cal/(g°C).
A) 1800 cal
B) 1600 cal
C) 2600 cal
2
D) 2800 cal
19. Calculate the heat required to condense 1.0 g of steam at 100oC to liquid water at 100oC.
Specific heat of water is 1.00 cal/(g°C).
Specific heat of vaporization is 540 cal/g.
Specific heat ofsteam (H2O (g)) is 0.48 cal/(g°C).
A) 540 cal
B) -540 cal
C) -540.48 cal
D) 540.48 cal
20. Which of the following statements is true?
A) Vapor pressure is not a function of the intermolecular attractions between molecules?
B) As the temperatures of liquid increases, its vapor pressure increases.
C) Boiling point is both a physical property and a chemical property of a liquid.
D) Hydrogen bonding is not related to vapor pressure.
21. Which of the following compounds has the highest boiling point, H2O, CH3OH, H2S, C3H6O
A) H2O
B) CH3OH
C) H2S
D) C3H6O
22. Which of the following has a bent molecular shape?
A) BF3
B) Cl2
C) H2O
D) CO2
23. Draw the electron dot structure for the nitrite ion, [NO2]–.
A)
O
N
O
C)
O
N
O
B)
O
D)
3
N
O
O
N
O
24. Draw the electron dot structure for the ammonium ion, [NH4]+.
H
H
A)
H
N
B)
H
H
N
H
H
H
H2
C)
H2
N
D)
N
H2
H2
25. Draw the electron dot structure for hydrogen cyanide, HCN.
A)
H
C
N
B)
C)
H
N
C
D)
4
H
C
N
H
C
N
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