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

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O-H…

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N-H.

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dip

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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