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Chemical bonds vs.intermolecular interactions
metallic bondscovalent bonds
~ 400 kJ/molionic bonds
~ 400 kJ/molpolar-covalent bonds
~ 400 kJ/mol
visible light 170-290 kJ/mol
ion-dipole 50-200 kJ/mol
heavy main group dispersion 5-100 kJ/mol
FH…H hydrogen bonds ~150 kJ/mol
OH…H hydrogen bonds ~ 20 kJ/mol
NH…H hydrogen bonds ~10 kJ/mol
room temperature 2.5 kJ/mol
dipole-dipole interactions 1-5 kJ/mol
light main group dispersion < 1 kj/mol
The threechemicalbonds
the miximbetween
The threeintermolecularinteractions
metallic bondscovalent bonds
~ 400 kJ/molionic bonds
~ 400 kJ/molpolar-covalent bonds
~ 400 kJ/mol
visible light 170-290 kJ/mol
ion-dipole 50-200 kJ/mol
heavy main group dispersion 5-100 kJ/mol
FH…H hydrogen bonds ~150 kJ/mol
OH…H hydrogen bonds ~ 20 kJ/mol
NH…H hydrogen bonds ~10 kJ/mol
room temperature 2.5 kJ/mol
dipole-dipole interactions 1-5 kJ/mol
light main group dispersion < 1 kj/mol
The threechemicalbonds
the miximbetween
The threeintermolelcularinteractions
dispersion interactions
the third intermolecular interaction: strong vs. weak dispersion interactions
F Br
ICl
F boilingpoint: -188o C
Cl boilingpoint: -34o C
Br boilingpoint: 59o C
I boilingpoint: 184o C
no dipoles and no hydrogen bondsin F2, Cl2, Br2 or I2.
Strong vs. weak dispersion interactions
F Br IClF b.p. -188o C Cl b.p.-34o C Br b.p. 59o C I b.p. 184o C
F − F Cl − Cl Br − Br I − I
The four Lewis structures are all similar. No dipoles; No ions; No hydrogen bonds
Pleaserationalizethe differentboiling pointsof thenoble gases.
covalent bonds ~ 400 kJ/mol
ionic bonds ~ 400 kJ/mol
polar-covalent bonds ~ 400 kJ/mol
visible light 170-290 kJ/mol
ion-dipole 50-200 kJ/mol
heavy main group dispersion 5-100 kJ/mol
FH…H hydrogen bonds ~150 kJ/mol
OH…H hydrogen bonds ~ 20 kJ/mol
NH…H hydrogen bonds ~10 kJ/mol
room temperature 2.5 kJ/mol
dipole-dipole 1-5 kJ/mol
light main group dispersion < 1 kj/mol
the one mix imbetween
NaCl (solid) Na+ (aqueous) + Cl- (aqueous)
ion-ion bond ~400 kJ/mol
Ion–dipole interaction ~100- 200 kJ/mol.
~400 kJ/mol
~200 kJ/mole
metallic bondscovalent bonds
~ 400 kJ/molionic bonds
~ 400 kJ/molpolar-covalent bonds
~ 400 kJ/mol
visible light 170-290 kJ/mol
ion-dipole 50-200 kJ/mol
heavy main group dispersion 5-100 kJ/mol
FH…H hydrogen bonds ~150 kJ/mol
OH…H hydrogen bonds ~ 20 kJ/mol
NH…H hydrogen bonds ~10 kJ/mol
room temperature 2.5 kJ/mol
dipole-dipole interactions 1-5 kJ/mol
light main group dispersion < 1 kj/mol
The threechemicalbonds
the miximbetween
The threeintermolecularinteractions
the three chemical bonds, the three intermolecular interactions and the one mix imbetween
~400 kJ/mole
~400 kJ/mole
F boilingpoint: -188o C
I
I boiling point: 184o C
~200 kJ/mole
metal bondscovalent bonds
~ 400 kJ/molionic bonds
~ 400 kJ/molpolar-covalent bonds
~ 400 kJ/mol
visible light 170-290 kJ/mol
ion-dipole 50-200 kJ/mol
heavy main group dispersion 5-100 kJ/mol
FH…H hydrogen bonds ~150 kJ/mol
OH…H hydrogen bonds ~ 20 kJ/mol
NH…H hydrogen bonds ~10 kJ/mol
room temperature 2.5 kJ/mol
dipole-dipole 0.5-3 kJ/mol
light main group dispersion < 1 kj/mol
The threechemicalbonds
the miximbetween
The threeintermolecularinteractions
ion-ion
covalent bond
heavy main group dispersion bond dipole moments
ion-dipole
F-H…F
O-H…O
N-H..N
light maingroupdispersion
Qatar
Connecticut corresponds to room temperature
ion-
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ain
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ion-
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F-H…
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O-H…
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N-H.
.N
light
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bond
dip
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mom
ents
bonds vs. intermolecular interactions
covalent bonds ~ 400 kJ/mol
ionic bonds ~ 400 kJ/mol
polar-covalent bonds ~ 400 kJ/mol
metal bonds
visible light 170-290 kJ/mol
ion-dipole 50-200 kJ/mol
heavy main group dispersion 5-100 kJ/mol
FH…H hydrogen bonds ~150 kJ/mol
OH…H hydrogen bonds ~ 20 kJ/mol
NH…H hydrogen bonds ~10 kJ/mol
room temperature 2.5 kJ/mol
dipole-dipole interactions 1-5 kJ/mol
light main group dispersion < 1 kj/mol
H3C-SiH3
Na+ … Cl-
Mg2+… O2- F-H ….OH2
H-C≅N….
….
N≅C-H
H2Te … TeH2
What are each of the types of interactions/bonds below?
Mg2+… OH2-
What interaction holds together the following pairs of molecules? What is roughly the energy of interactionin kJ/mole?
a) two NF3 molecules
b) two BiF3 molecules
c) two F2 molecules
d) two HF molecules
e) an H2O molecule and an HF molecule
f) two CH4 molecules
covalent bonds ~ 400 kJ/mol
ionic bonds ~ 400 kJ/mol
polar-covalent bonds ~ 400 kJ/mol
metallic bonds
visible light 170-290 kJ/mol
ion-dipole 50-200 kJ/mol
heavy main group polarization 5-100 kJ/mol
FH…H hydrogen bonds ~150 kJ/mol
OH…H hydrogen bonds ~ 20 kJ/mol
NH…H hydrogen bonds ~10 kJ/mol
room temperature 2.5 kJ/mol
dipole-dipole (< 2 D, Dc 1st-2nd row) 0.5-3 kJ/mollight main group polarization < 1 kj/mol
Are X and Y 1st and 2nd
row elements?
Do heavy main groupinteractions exist?
Do F-H…F bonds exist?
Do O-H…O bonds exist?
Do N-H…N bonds exist?
covalent bond
heavy main group dispersion
F-H…F O-H…O N-H…N
yes
yes yes yes
Calculate DcIs Dc < 0.5 Debye?
Is Dc > 1 Debye?
light main group polarization
dipole-dipole interaction
yes
yes
yes
no
no
no
no
What interaction holds together the following pairs of molecules? What is roughly the energy of interactionin kJ/mole?
a) two NF3 molecules
b) two BiF3 molecules
c) two F2 molecules
d) two HF molecules
e) an H2O molecule and an HF molecule
f) two CH4 molecules
For now compare boiling points for molecules with roughly the same molecular mass.
Why do the boiling points occur in the order in which they do?
Where would formic acid, HCO2H with molecular weight 46 g/mol appear on this boiling pointchart?
How would CH3SeSeCH3 and I2 approach one another?
How would RSeSeR and I2 approach one another?
Salad dressing is composed of oil and vinegar (that is hydrocarbons, CH3(CH2)nCH3, water, and acetic acid, CH3COOH.
Why do oil and vinegar not mix?
A typical soap compound is sodium stearate. Why is soap good at removing the oil fromthe skin?
sodium stearate
A typical soap compound is sodium stearate. Why is soap good at removing the oil fromthe skin?
sodium stearate
rule: like adheres to like.
The larger the molecule, the greater number of similarintermolecular interactions the molecule can have.
two additional factors which control intermolecular interactions (1) size
The boiling point depends upon the number of atoms on the molecule’s surface available for intermolecular interactions.
and (2) shape.
determining molecular shape:ionic bonds vs. covalent bonds
Determine molecular shape of:
a) NF3
b) MgO
c) CH3COCH3
d) TiO2
Determine molecular shape of:
NF3
MgO
CH3COCH3
TiO2
Mooser-Pearson
What can you deduce about the molecular shape of the following ions/compounds?
a) CaS
b) Si
c) SiF62-
d) NaI3
e) HC(CH3)3
H3C-SiH3
Na+ … Cl-
Mg2+… O2- F-H ….OH2
H-C≅N….
….
N≅C-H
H2Te … TeH2
What are each of the types of interactions/bonds below?
Mg2+… OH2-
review slie 1
What interaction holds together the following pairs of molecules? What is roughly the energy of interactionin kJ/mole?
a) two NF3 molecules
b) two BiF3 molecules
c) two F2 molecules
d) two HF molecules
e) an H2O molecule and an HF molecule
f) two CH4 moleculesreview slie 2
What can you deduce about the molecular shape of the following ions/compounds?
a) CaS
b) Si
c) SiF62-
d) NaI3
e) HC(CH3)3
review slie 3
Two proportionality questions
a) If a series of chemically similar molecules (made from the same combination of elements) are all shaped like spheres,what is the proportionality relation between molecular mass and boiling point?
b) If a series of chemically similar molecules (made from the same combination of elements) are all shaped like chains, with almost every bond on the surface of the molecule,what is the proportionality relation between molecular mass and boiling point?
homework
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