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Base your answers to questions
I and 2 on the
information below.
Ozone, O:(g), is produced from oxygen, O:(g) by
electrical discharge during thunderstonns. The
unbalanced equation below represents the reaction that
fomrs ozone.
.
{).,,''
l.
l,
"ri'
.-'{',
rt',
',
Explain, in terms of electron configuration, rvhy an
oxygen molecule is morc stable than an oxygen atom.
2. Identify the type of bonding between the atoms in an
oxygeu rnolecule.
Base your answers to questions 3 and 4 on the infbrmation below.
Physical Properties of CF4 and NH3
at Standard Pressure
Melting
Point
( t'l
Boiling
Foint
{"c}
$olubility in
Compound
CF.
*183.6
-127 8
insoluble
NH,:
1'7
_JJ.J
soiuble
-7
Water at
- 20.0'c
3. State evidence that indicates NH: has stronger intennolecular forces than CF+.
4. In tlre space in v-oL!t'ailsv,€t' boolilet, draw a Lewis electron-dot diagram fol CF+.
5. Explain, in terns of electronegativity difference, why the bond in a molecule of HF is more polar than the
bond in a molecule of HI.
6.
Base your answer to the fbllowing qucstion on the infbrmation below.
Carbon has three naturally occurring isotopes, C-12, C-13, and C-14. Diarnond and graphite are
familiar forms of solid carbon. Diamond is one of the hardest substances known, while graphite is a very
solt substance. Diamoud has a rigid rretwork of bonded atorns. Graphite has atoms bonded in thin layers
that are held together by weak forces.
Recent experitnents have produced new forms of solid carbon called fullerenes. One fullerene, Ccq
is a spherical" cagelike molecule of carbon.
State. in terms of the affangement of atoms, the difTerence in hardness between diamond and graphite.
Basc your answers to questions 7 and 8 on thc information below.
Bond energy is the amount of energy requiled to break a chemical bond. The table below gives
fbrrnula and the carbon-nitrogen bond energy fbr selected nitrogen compounds.
a
$elected Nitrogen Compaunds
Cerbon-Nitrogen
Sond Energy
Compound
Formula
hydrogen cyanide
H_C=N
{kJimo{)
890.
H*N:C:O
615
rsocyanic acjd
i-{
I
H-C-N-H
meihanamine
!t
t"{
293
H
7. Explain, in tetms of charge distribution, why a molecule of hydrogen cyanide is polar'.
8. State the relationship between the number of electrons in a carbon-nitrogen bond and carbon-nitrogen bond
energy.
9. Explain, in terms of molecular stmcture or distribution of charge, why a molecule of methane is nonpolar.
10. Drarv a Lewis elcctron-dot diagram for a molecule of phosphonrs trichloride" PClr
I 1. Base your answer to the fbllowing question on your
knowledge of chemicalbonding and on the l-ewis
electron-dot diagrams of HzS, COz, and F: below.
H:S:
lO::C::Ol
:F:F:
H
Explain, in terms of electronegativity, why a C,O bond
in CO: is more polar than the F-F bond in Fz.
Base your answers to questions 12 and 13 on the
inforrnation below.
Each molecule listed below is fbnned by sharing
electrons betu'een atoms u4ren the atoms within the
molecule are bonded togetlier.
Molecule A: Clz Molecule B; CCI+ Molecule C NH:
12. Explain how the bonding in KCI is difl-erent fiom the
bonding in molecules A, B, and C.
13. Explain why NH: has stronger intermolecular forces
attraction than Cl:.
of
14. Draw an electron-dot diagram for each of the following substances:
a calcium oxide (an ionic compound)
b hydrogen bromide
c carbon dioxide
15. Draw the electron-dot (Lewis) structure of calcium
chloride.
16. Base your answer to the fbllowing question on Base your answers to the question below on diagram and
description below:
A crystal of potassium chloride is shown below. The larger dark circles and the smaller open
circles represent the ions.
c What is the empirical formula of potassium chloride?
b Would it be possible for magnesium
chloride to have the same exact structure as potassium chloride?
Explain.
c
When dissolved in water, potassium chloride is a good conductor of electricity, while solid potassium
chloride is not. Explain.
17. Base your answer to the following question on An unknown solid was tested and showed the properties
listed below:
Properties
high melting point
soluble in water
conductor of electricity when dissolved in water
non-conductor of electricity as a solid
hard surface
rz
State the rype of bonding you would expect of tliis substance.
6
Explain why this substance conducts electricity when dissolved in water.
c
Explain why it is hard.
18. Base your arlswer to the following question on An unknown solid was tested and showed the properties
listed below:
Properties
low mclting point
nearly insoluble in water
non-conductor of electricity
relatively soft solid
a)
State the type of bonding you would expect of this substance.
b)
Explain why this substance is insoluble in water.
c) Explain why it is soft.
19. a) Draw the stmctural formula for HzO.
b) Is this molecule polar or nonpolar? Explain your
answer.
20. When hydrogen bromide,
a gas, is dissolved in water, the solution is called hydrobromic acid
a
Draw the Lewis electron-dot strucrure fbr a molecule of hydrogen bromide, HBr.
b
Is hydrogen bromide a polar or non-polar molecule? Explain
21. Base your answer to the following question on Nitrogen
is a Group l5 element u'hich makes up about 78o/o of
thc atmosphere by volume. Nitrogen is a colorless,
odorless, tasteless diatomic gas. It does not bum, does
not suppoft combustion. and is only slightly soluble in
water. It is relatively inactive chemically.
Nitrogen is present in the protoplasm of all living
matter; it and its compounds are necessary for the
continuation of life. Nitrogen is present in foods and is
impoftant in the human diet.
cz Draw the Lewis electron-dot structure for a molecule
of nitrogen, Nz.
b Why can't hurnans get nitrogen for their diets by
breathing air?
22. Base your answer to the following question on Carbon dioxide is a colorless, odorless gas produced by
respiration and combustion of carbon-containing fuels. It is slightly soluable in water.
Draw the Lewis electron-dot structure fbr a molecule of carbon dioxide, COz.
23. Base your answer to the fbllowing question on Water is a polar molecule because it is bent and has
a
definite positive and negative side to it.
a
Draw the Lewis electron-dot stmcture for a molecule of water, HzO.
b
Onyourdrawing indicate with a " + " the.positive side andwith a "
- " the negative
side.
c
Describe one propefty of water that would chan-{e if the water molecule were a straight molecule and
non-polar.
24. Ammonia is an electrolyte because, when dissolved in water, it produces ions by the lbllowing reaction:
NHr(aq) +
a Draw
HzO,
NH+*(aq) + OH1aq)
the Lewis electron-dot structure for a molecule of ammonia.
b Draw the Lewis electron-dot
NH:.
structure fbr a molecule of ammonium ion, NH.r*.
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