1. Which best describes the energy change during the
reaction?
5. Consider the sets of charged objects shown in the
diagram:
H2(g) + Cl2(g) ® 2 HCl(g)
A)
B)
C)
D)
E)
Breaking the H–H bond releases energy
Breaking the Cl–Cl bond releases energy
Forming the H–Cl bond absorbs energy
Forming the H–Cl bond releases energy
Breaking the H–CL bond releases energy
2. The attractive force between the protons of one molecule
and the electrons of another molecule are strongest
A) in the solid phase B) in the liquid phase
C) in the gaseous phase D) during sublimation
E) during fusion
3. Given the pure substances and their bond dissociation
energies, which substance is the most difficult to
decompose into its atoms?
A) HI 295 kJ•mol–1
C) H2 432 kJ•mol–1
E) HF 570 kJ•mol –1
B) HCl 428 kJ•mol –1
D) O2 494 kJ•mol–1
4. Covalent bonds are the result of the
A)
B)
C)
D)
E)
attraction of electrons to each other
attraction of an electron pair by two nuclei
elevation of electrons to higher energy levels
transfer of electrons from one atom to another
the attraction of two nuclei to eachother
Which is true?
A)
B)
C)
D)
E)
I and III are examples of attractive forces
The largest attractive force is case II
The largest repulsive force is case I
The attractive force in II is twice that in IV
The largest repulsive force is case II
6. Base your answer to the following question on the table
below. Consider the shell electron configuration of five
elements.
Which will form covalent compounds?
A) I and II
C) III and V
E) IV and V
B) I and IV
D) III and IV
7. A covalent bond is most likely to form between atoms of
chlorine and
A) iron
C) phosphorus
E) sodium
B) magnesium
D) potassium
8. Which is a fundamental definition of a chemical bond?
A) Positive ions attracting negative ions.
B) Transfer of electrons from one atom to another.
C) Attraction between valence electrons from two
atoms.
D) Electrons simultaneously attracted by more than
one nucleus.
E) Nuclei simultaneously attracted to more than one
electron.
9. The term electronegativity is used because
A) some elements conduct electricity and others do
not.
B) an electric current is a stream of negative particles.
C) it requires energy to remove electrons from neutral
atoms.
D) the nucleus is negatively charged.
E) the attraction for electrons in a bond formed
between two different atoms can be uneven.
10. The greater the electronegativity of an element, the
greater the tendency of the element to
A) gain electrons.
C) gain protons.
E) form cations.
16. What is the type of binding force between phosphorus
and hydrogen in the compound PH 3?
A)
B)
C)
D)
E)
ionic bonding
covalent bonding
hydrogen bonding
van der Waals forces
metallic bonding
17. Which type of bond is present in CS 2?
A) network
B) electrovalent
C) polar covalent
D) metallic
E) nonpolar covalent
18. Which compound contains covalent bonds?
A) BeO
B) MgF 2 C) NaCl D) SO 2
E) CaS
19. Which compound contains a covalent bond with the
greatest polarity?
A) HF
B) H2O
C) BBr3 D) CCl4 E) Cl 2
20. Which pair of elements forms the most polar bond?
B) lose electrons.
D) lose protons.
11. Which compound has the greatest ionic character in its
bonds?
A) KCl
B) CaCl2 C) GaCl3 D) AsCl3 E) O2
12. Which element exists as diatomic molecules at STP?
A) copper
C) hydrogen
E) chromium
B) helium
D) silicon
13. Which compound has double covalent bonds?
A) CsCl B) CO 2
C) CCl4 D) H2O
E) NaF
14. What force or bond holds the two nitrogen atoms
together in a molecule of nitrogen gas, N 2?
A)
B)
C)
D)
E)
ionic bond
hydrogen bond
nonpolar covalent bond
van der Waals force
polar covalent bond
15. Which bond has the least ionic character?
A) S–Cl
C) Br–Cl
E) Na–Cl
B) H–Cl
D) Cl–Cl
A) O and Cl
C) O and P
E) Br and Cl
B) Cl and Br
D) P and Br
21. Which is the most polar bond?
A) C–O
B) C–N
C) B–O D) B–N
E) Cl–Cl
22. The bond formed between two nonmetallic atoms with
different electronegativities is the
A) ionic
B) metallic
C) polar covalent
D) nonpolar covalent
E) coordinate covalent
23. Which type of bonding is usually exhibited when the
electronegativity difference between two atoms is 1.1?
A)
B)
C)
D)
E)
ionic
covalent
metallic
network
bonding will not occur
24. Which formula has bonds with the most ionic
character?
A) O–H B) O=O C) C=O D) B–Cl E) C–H
25. The bonding of H + to NH3 to form NH4+ is
A)
B)
C)
D)
E)
coordinate covalent
ionic
metallic
van der Waals
nonpolar covalent
26. A coordinate covalent bond is one in which
A) two atoms are bonded by one electron
B) one atom shares two of its electrons with
another atom
C) two atoms each contribute one electron to a
common bond
D) two atoms each contribute two electrons to a
common bond
E) two atoms with opposing charges attract each
other
27. In the diagram of an ammonium ion to the right, why is
bond A considered to be a coordinate covalent bond?
A) Hydrogen provides a pair of electrons to be shared
with nitrogen.
B) Nitrogen provides a pair of electrons to be
shared with hydrogen.
C) Hydrogen transfers a pair of electrons to the
nitrogen.
D) Nitrogen transfers a pair of electrons to hydrogen.
E) Hydrogen and nitrogen each provide an electron.
28. Diamond and graphite both have bonds which are
predominantly
A) ionic
C) covalent
E) coordinate
B) metallic
D) network
29. Which of the following compounds is nonpolar?
A) HCl
C) CHCl 3
E) none of the above
B) NH 3
D) AlCl 3
30. Which of the following molecules is nonpolar?
A) H2O
C) CO 2
E) CO
B) NH 3
D) CHCl 3
31. Potassium chloride dissolved in pure water is an
example of
A)
B)
C)
D)
an ionic compound dissolved in a polar solvent
an ionic compound dissolved in a nonpolar solvent
a covalent compound dissolved in a polar solvent
a covalent compound dissolved in a nonpolar
solvent
E) an ionic molecule mixed with a polar compound
32. The water molecule is
A) ionic.
C) electrovalent.
E) linear.
B) a dipole.
D) a macromolecule.
33. Consider the elements and their first ionization energies. 37. Which molecule is nonpolar?
A)
C)
B)
D)
E)
38. Which molecule is not a dipole?
A)
B)
Three compounds are formed.
Which statement concerning the three molecules is
true?
C)
D)
A)
B)
C)
D)
E)
I and II are polar; III is nonpolar.
I and II have the same degree of polarity.
The bond angles in molecules I and II are identical.
Electrons are attracted more strongly to B than to
C.
E) Electrons are attracted less to C than to B.
34. Which molecules are polar?
39. In ice, the molecules of H 2O(s) are held together by
A)
B)
C)
D)
E)
covalent bonds.
hydrogen bonds.
ionic bonds.
oxygen bonds.
Van der Waals forces.
40. Which statement best accounts for the boiling point of
H2O being considerably higher than that of H 2S?
A)
B)
C)
D)
A) I and IV only
C) II, III and V only
E) all of these
The molecular mass of H2O is lower.
Van der Waals forces are greater in H 2O.
London dispersion forces are greater in H 2O.
H2O molecules have more unshared pairs of
valence electrons.
E) Hydrogen bonding is more pronounced in H 2O.
B) II and IV only
D) III and V only
35. The compound that is a polar covalent molecule is
A) CsCl B) CO 2
C) CCl4 D) SF6
36. Which is a polar molecule?
A)
B)
C)
D)
E) H 2O
41. Why is the heat of vaporization of H 2O (2270 J) so
much higher than that of C8H18 (590 J)?
A)
B)
C)
D)
octane molecules are polar.
molecules of water are less massive.
octane gives off little energy when it vaporizes.
the forces of attraction are stronger between
water molecules.
E) the forces of attraction are stronger within octane
molecules.
42. Which substance has a high attraction for water
molecules and a high solubility in water?
A) I and IV only
C) III and V only
E) V only
A)
B)
C)
D)
B) II and IV only
D) IV and V only
43. The bonds between molecules in solid nitrogen are
A)
B)
C)
D)
E)
48. Which diagram shows the orientation of the water
molecules and the calcium ions when calcium chloride
is dissolved in water?
Van der Waals forces
covalent bonds
hydrogen bonds
ionic bonds
network bonds
49. Which Lewis electron dot diagram is correct?
A)
B)
C)
D)
E)
44. Which molecular solid has only van der Waals forces as 50. The Lewis electron dot diagram for CO 2 is
intermolecular bonding?
A)
B)
A) KI
B) HF
C) H2S D) NH 3 E) CO 2
C)
D)
45. Which substance in the solid state consists of particles
E)
held together by van der Waals forces only?
A) Ge
B) Rb
C) KCl
D) SiO2
E) CH 4
46. In which substance is the primary attraction van der
Waals forces?
51. Which is the correct Lewis electron dot diagram for NH
3?
A)
B)
C)
D)
E)
A) I
B) II
C) III
D) IV
E) V
47. Water and oil do not mix because
A)
B)
C)
D)
E)
their densities are different
oil is a polar liquid
water is a nonpolar liquid
weak bonds form between oil and water
no bonds form between oil and water
52. All of the following are resonance structures for NO3–
except
A)
B)
C)
D)
53. The bonding orbitals on the central atom in a CF 4
molecule are
A) s orbitals
C) sp orbitals
E) sp 3 orbitals
B) p orbitals
D) sp 2 orbitals
54. In which compound is
bonding?
A) BH 3
sp2
hybridization present in the
B) C2H2 C) CH 4
D) H2O
E) CO
55. Which hybridization of orbitals is present in the
ammonium ion, NH 4+ ?
A) sp
B)
sp 2
C)
sp 3
D)
dsp 3
56. Carbon dioxide is
A)
B)
C)
D)
E)
linear and polar
linear and nonpolar
bent and polar
bent and nonpolar
trigonal planar and polar
57. The shape of methane molecules, CH4, is
A) bent
C) tetrahedral
E) planar
B) triangular
D) octahedral
E)
58. The shape of an NH3 molecule is
A) linear
C) planar triangular
E) bipyramidal
B) tetrahedral
D) trigonal pyramidal
59. The bonding orbitals on the boron atom in BF 3
molecule are
A) s orbitals
C) sp 2 orbitals
E) p orbitals
B) sp orbitals
D) sp 3 orbitals
60. The shape of a water molecule is
spd 3
A) bent
C) pyramidal
E) octahedral
B) planar
D) tetrahedral
61. The shape of CH2Cl 2 is
A) linear
C) pyramidal
E) seesaw
B) planar
D) tetrahedral
Answer Key
Unit 8 Practice Test
1.
D
37.
B
2.
A
38.
D
3.
E
39.
B
4.
B
40.
E
5.
B
41.
D
6.
A
42.
C
7.
C
43.
A
8.
D
44.
E
9.
E
45.
E
10.
A
46.
C
11.
A
47.
D
12.
C
48.
B
13.
B
49.
B
14.
C
50.
C
15.
D
51.
C
16.
B
52.
C
17.
E
53.
E
18.
D
54.
A
19.
A
55.
C
20.
C
56.
B
21.
C
57.
C
22.
C
58.
D
23.
B
59.
C
24.
A
60.
A
25.
A
61.
D
26.
B
27.
B
28.
D
29.
E
30.
C
31.
A
32.
B
33.
A
34.
C
35.
E
36.
B