Transcript London Dispersion - stoweschools.com

1. What determines the state of matter a molecule is at
room temperature? What determines the ability of a
molecule to develop cohesive and adhesive forces?
1. What determines the state of matter a molecule is at
room temperature? What determines the ability of a
molecule to develop cohesive and adhesive forces?
• Intermolecular forces of attraction such as
london dispersion, dipole dipole attractions
and hydrogen bonding determine
attractions between molecules.
IMF
• 2. What type of molecules can attract each other through London
dispersion forces?
•
All molecules will attract each other through London Dispersion
Forces
• 3. What does dispersion mean?
•
Dispersion means to spread out
• 4. How does dispersion create polarity in molecules?
•
One sided momentary Shifts in electrons caused by this dispersion
create short lived positive and negative regions.
• 5. What force of attraction causes attractions between molecules?
•
Positive and Negative Regions cause electrostatic attractions
between molecules.
IMF
• 2. What type of molecules can attract each other through London
dispersion forces?
•
All molecules will attract each other through London Dispersion
Forces
• 3. What does dispersion mean?
•
Dispersion means to spread out
• 4. How does dispersion create polarity in molecules?
•
One sided momentary Shifts in electrons caused by this dispersion
create short lived positive and negative regions.
• 5. What force of attraction causes attractions between molecules?
•
Positive and Negative Regions cause electrostatic attractions
between molecules.
IMF
• 2. What type of molecules can attract each other through London
dispersion forces?
•
All molecules will attract each other through London Dispersion
Forces
• 3. What does dispersion mean?
•
Dispersion means to spread out
• 4. How does dispersion create polarity in molecules?
•
One sided momentary Shifts in electrons caused by this dispersion
create short lived positive and negative regions.
• 5. What force of attraction causes attractions between molecules?
•
Positive and Negative Regions cause electrostatic attractions
between molecules.
IMF
• 2. What type of molecules can attract each other through London
dispersion forces?
•
All molecules will attract each other through London Dispersion
Forces
• 3. What does dispersion mean?
•
Dispersion means to spread out
• 4. How does dispersion create polarity in molecules?
•
One sided momentary Shifts in electrons caused by this dispersion
create short lived positive and negative regions.
• 5. What force of attraction causes attractions between molecules?
•
Positive and Negative Regions cause electrostatic attractions
between molecules.
IMF
• 2. What type of molecules can attract each other through London
dispersion forces?
•
All molecules will attract each other through London Dispersion
Forces
• 3. What does dispersion mean?
•
Dispersion means to spread out
• 4. How does dispersion create polarity in molecules?
•
One sided momentary Shifts in electrons caused by this dispersion
create short lived positive and negative regions.
• 5. What force of attraction causes attractions between molecules?
•
Positive and Negative Regions cause electrostatic attractions
between molecules.
London dispersion forcesmomentary shifts
London Dispersion Forces
• 6. What effect does the size of a molecule have on the
strength of London Dispersion Forces?
Larger and heavier atoms and molecules exhibit
stronger dispersion forces than smaller and lighter
ones. In a larger atom or molecule, the valence
electrons are, on average, farther from the nuclei than
in a smaller atom or molecule. They are less tightly
held and can more easily form temporary dipoles
London Dispersion Forces
• 6. What effect does the size of a molecule have on the
strength of London Dispersion Forces?
Larger and heavier atoms and molecules exhibit
stronger dispersion forces than smaller and lighter
ones. In a larger atom or molecule, the valence
electrons are, on average, farther from the nuclei than
in a smaller atom or molecule. They are less tightly
held and can more easily form temporary dipoles
IMF
• F2 with a mass of 38 is a gas,
• Cl2 with a mass of 71 is a gas
Br2 with a mass of 160 is a liquid,
I2 with a mass 254 of is a solid at room temp.
These are all non polar molecules from the same
group in the periodic table.
Dipole Dipole
• 7. What type of molecules attract each other through
•
Dipole Dipole interactions
• Molecules that contain polar covalent bonds and
asymmetrical shapes have permanent positive end and
a negative regions.
• The permanent force of attraction between these positive
and negative regions are referred to as a dipole-dipole
attraction.
• antoine.frostburg.edu/chem/senese/101/liquids/faq/hbonding-vs-london-forces.shtml
Dipole Dipole
• 7. What type of molecules attract each other through
•
Dipole Dipole interactions
• Molecules that contain polar covalent bonds and
asymmetrical shapes have permanent positive end and
a negative regions.
• The permanent force of attraction between these positive
and negative regions are referred to as a dipole-dipole
attraction.
• antoine.frostburg.edu/chem/senese/101/liquids/faq/hbonding-vs-london-forces.shtml
•
•
•
IMF
8. What is hydrogen bonding?
It is a special case of Dipole-Dipole
Hydrogen bonded to N O F
• 9. What characteristics do the atoms bonded to H have?
• The Nitrogen, Oxygen and Fluorine are small highly electronegative
atoms that develop substantial partial negative charges when they
bond with hydrogen which in turn develops a substantial positive
charge.
• The partially positive hydrogen of one molecule is attracted to the
partially negative portion of another molecule.
• 10. Are hydrogen bonds the same as covalent bonds?
• Hydrogen bonds are between molecules not within in molecules and
are much weaker than covalent bonds
•
•
•
IMF
8. What is hydrogen bonding?
It is a special case of Dipole-Dipole
Hydrogen bonded to N O F
• 9. What characteristics do the atoms bonded to H have?
• The Nitrogen, Oxygen and Fluorine are small highly electronegative
atoms that develop substantial partial negative charges when they
bond with hydrogen which in turn develops a substantial positive
charge.
• The partially positive hydrogen of one molecule is attracted to the
partially negative portion of another molecule.
• 10. Are hydrogen bonds the same as covalent bonds?
• Hydrogen bonds are between molecules not within in molecules and
are much weaker than covalent bonds
•
•
•
IMF
8. What is hydrogen bonding?
It is a special case of Dipole-Dipole
Hydrogen bonded to N O F
• 9. What characteristics do the atoms bonded to H have?
• The Nitrogen, Oxygen and Fluorine are small highly electronegative
atoms that develop substantial partial negative charges when they
bond with hydrogen which in turn develops a substantial positive
charge.
• The partially positive hydrogen of one molecule is attracted to the
partially negative portion of another molecule.
• 10. Are hydrogen bonds the same as covalent bonds?
• Hydrogen bonds are between molecules not within in molecules and
are much weaker than covalent bonds
•
•
•
IMF
8. What is hydrogen bonding?
It is a special case of Dipole-Dipole
Hydrogen bonded to N O F
• 9. What characteristics do the atoms bonded to H have?
• The Nitrogen, Oxygen and Fluorine are small highly electronegative
atoms that develop substantial partial negative charges when they
bond with hydrogen which in turn develops a substantial positive
charge.
• The partially positive hydrogen of one molecule is attracted to the
partially negative portion of another molecule.
• 10. Are hydrogen bonds the same as covalent bonds?
• Hydrogen bonds are between molecules not within in molecules and
are much weaker than covalent bonds
Molecules that hydrogen bond.
11. How does Hydrogen Bonding affect the boiling
points of molecules that can H-bond?
H2O, HF, and NH3 have much higher boiling points
than similar molecules because of hydrogen bonding.
11. How does Hydrogen Bonding affect the boiling
points of molecules that can H-bond?
H2O, HF, and NH3 have much higher boiling points
than similar molecules because of hydrogen bonding.
12. Intermolecular Forces
Questions
•
•
•
•
HBr HBr attract each by
I) London Dispersion Forces
II) Dipole Dipole Attractions
III) Hydrogen bonding
I and II
Why?
All molecules undergo momentary shifts that characterize
London Dispersion Forces
HBr – nm to nm E.D. 2.8 – 2.2 = .6 Polar covalent
Dipole to Dipole Attractions are found between asymmetrical
molecules containing polar covalent bonds
12. Intermolecular Forces
Questions
•
•
•
•
HBr HBr attract each by
I) London Dispersion Forces
II) Dipole Dipole Attractions
III) Hydrogen bonding
I and II
Why?
All molecules undergo momentary shifts that characterize
London Dispersion Forces
HBr – nm to nm E.D. 2.8 – 2.2 = .6 Polar covalent
Dipole to Dipole Attractions are found between asymmetrical
molecules containing polar covalent bonds
12. Intermolecular Forces
Questions
•
•
•
•
HBr HBr attract each by
I) London Dispersion Forces
II) Dipole Dipole Attractions
III) Hydrogen bonding
I and II
Why?
All molecules undergo momentary shifts that characterize
London Dispersion Forces
HBr – nm to nm E.D. 2.8 – 2.2 = .6 Polar covalent
Dipole to Dipole Attractions are found between asymmetrical
molecules containing polar covalent bonds
12. Intermolecular Forces
Questions
•
•
•
•
HBr HBr attract each by
I) London Dispersion Forces
II) Dipole Dipole Attractions
III) Hydrogen bonding
I and II
Why?
All molecules undergo momentary shifts that characterize
London Dispersion Forces
HBr – nm to nm E.D. 2.8 – 2.2 = .6 Polar covalent
Dipole to Dipole Attractions are found between asymmetrical
molecules containing polar covalent bonds
13. Intermolecular Forces
• CH3OH
•
•
HOCH3
• The above attract each other by
•
•
•
I) London Dispersion Forces
II) Dipole Dipole Attractions
III) Hydrogen bonding
•
I and III
I
All molecules undergo momentary shifts that characterize London
Dispersion Forces
III CH3OH contains a Hydrogen bonded to an oxygen which is
attracted to the oxygen of a neighboring molecule which is
characteristic of hydrogen bonding
13. Intermolecular Forces
• CH3OH
•
•
HOCH3
• The above attract each other by
•
•
•
I) London Dispersion Forces
II) Dipole Dipole Attractions
III) Hydrogen bonding
•
I and III
I
All molecules undergo momentary shifts that characterize London
Dispersion Forces
III CH3OH contains a Hydrogen bonded to an oxygen which is
attracted to the oxygen of a neighboring molecule which is
characteristic of hydrogen bonding
13. Intermolecular Forces
• CH3OH
•
•
HOCH3
• The above attract each other by
•
•
•
I) London Dispersion Forces
II) Dipole Dipole Attractions
III) Hydrogen bonding
• I and III
Why?
I All molecules undergo momentary shifts that characterize London
Dispersion Forces
III CH3OH contains a Hydrogen bonded to an oxygen which is
attracted to the oxygen of a neighboring molecule which is
characteristic of hydrogen bonding
13. Intermolecular Forces
• CH3OH
•
•
HOCH3
• The above attract each other by
•
•
•
I) London Dispersion Forces
II) Dipole Dipole Attractions
III) Hydrogen bonding
• I and III
Why?
I All molecules undergo momentary shifts that characterize London
Dispersion Forces
III CH3OH contains a Hydrogen bonded to an oxygen which is
attracted to the oxygen of a neighboring molecule which is
characteristic of hydrogen bonding
13. Intermolecular Forces
• CH3OH
•
•
HOCH3
• The above attract each other by
•
•
•
I) London Dispersion Forces
II) Dipole Dipole Attractions
III) Hydrogen bonding
• I and III
Why?
I All molecules undergo momentary shifts that characterize London
Dispersion Forces
III CH3OH contains a Hydrogen bonded to an oxygen which is
attracted to the oxygen of a neighboring molecule which is
characteristic of hydrogen bonding
14. Intermolecular Forces
•
•
•
•
•
•
CH4
CH4
The above attract each other by
I) London Dispersion Forces
II) Dipole Dipole Attractions
III) Hydrogen bonding
• I only
Why?
I All molecules undergo momentary shifts that characterize London
Dispersion Forces
C nonmetal H nonmetal E.D 2.6 – 2.2 = .4 Nonpolar covalent
Nonpolar molecules can only attract each other by nonpolar covalent
bonds.
14. Intermolecular Forces
•
•
•
•
•
•
CH4
CH4
The above attract each other by
I) London Dispersion Forces
II) Dipole Dipole Attractions
III) Hydrogen bonding
• I only
Why?
I All molecules undergo momentary shifts that characterize London
Dispersion Forces
C nonmetal H nonmetal E.D 2.6 – 2.2 = .4 Nonpolar covalent
Nonpolar molecules can only attract each other by nonpolar covalent
bonds.
14. Intermolecular Forces
•
•
•
•
•
•
CH4
CH4
The above attract each other by
I) London Dispersion Forces
II) Dipole Dipole Attractions
III) Hydrogen bonding
• I only
Why?
I All molecules undergo momentary shifts that characterize London
Dispersion Forces
C nonmetal H nonmetal E.D 2.6 – 2.2 = .4 Nonpolar covalent
Nonpolar molecules can only attract each other by nonpolar covalent
bonds.
14. Intermolecular Forces
•
•
•
•
•
•
CH4
CH4
The above attract each other by
I) London Dispersion Forces
II) Dipole Dipole Attractions
III) Hydrogen bonding
• I only
Why?
I All molecules undergo momentary shifts that characterize London
Dispersion Forces
C nonmetal H nonmetal E.D 2.6 – 2.2 = .4 Nonpolar covalent
Nonpolar molecules can only attract each other by nonpolar covalent
bonds.
14. Intermolecular Forces
•
•
•
•
•
•
CH4
CH4
The above attract each other by
I) London Dispersion Forces
II) Dipole Dipole Attractions
III) Hydrogen bonding
• I only
Why?
I All molecules undergo momentary shifts that characterize London
Dispersion Forces
C nonmetal H nonmetal E.D 2.6 – 2.2 = .4 Nonpolar covalent
Nonpolar molecules can only attract each other by nonpolar covalent
bonds.
15. How do hydrogen bonds form between water
molecules?
15. How do hydrogen bonds form between water
molecules?
16. Why can Carbon’s form 4 equivalent covalent
bonds?
• It can undergo sp3 hybridization in which a 2s electron
moves into a vacate 2p orbital creating an exicited state
in which the 2s and the three 2p’s are half filled.
•
• The half filled 2s and three 2p orbitals then
change ( hybridize ) into 4 equivalent sp3 orbitals
that allow carbon to form 4 bonds
16. Why can Carbon’s form 4 equivalent covalent
bonds?
• It can undergo sp3 hybridization in which a 2s electron
moves into a vacate 2p orbital creating an exicited state
in which the 2s and the three 2p’s are half filled.
•
• The half filled 2s and three 2p orbitals then
change ( hybridize ) into 4 equivalent sp3 orbitals
that allow carbon to form 4 bonds
16. Why can Carbon’s form 4 equivalent covalent
bonds?
• It can undergo sp3 hybridization in which a 2s electron
moves into a vacate 2p orbital creating an exicited state
in which the 2s and the three 2p’s are half filled.
•
• The half filled 2s and three 2p orbitals then
change ( hybridize ) into 4 equivalent sp3 orbitals
that allow carbon to form 4 bonds
sp3 hybridization
sp3 hybridization
•
www.mhhe.com/physsci/chemistry/carey5e/Ch02/ch2-3-1.html
17. Where does the overlap of atomic orbitals occur when a
Sigma covalent bond forms?
• The overlap occurs between the two nuclei involved in the
bond
17. Where does the overlap of atomic orbitals occur when a
Sigma covalent bond forms?
• The overlap occurs between the two nuclei involved in the
bond
17. Where does the overlap of atomic orbitals occur when a
Sigma covalent bond forms?
• The overlap occurs between the two nuclei involved in the
bond
18. Where does the overlap occur
when pi bonds form
Atomic Oribitals
Molecular Orbitals
• The overlap of orbitals does not occur between
the nuclei, it occurs above and below the two
nuclei or in front and back of the two nuclei
18. Where does the overlap occur
when pi bonds form
Atomic Oribitals
Molecular Orbitals
• The overlap of orbitals does not occur between
the nuclei, it occurs above and below the two
nuclei or in front and back of the two nuclei
18. Where does the overlap occur
when pi bonds form
Atomic Oribitals
Molecular Orbitals
• The overlap of orbitals does not occur between
the nuclei, it occurs above and below the two
nuclei or in front and back of the two nuclei
19. What type of bonds form in Ethane that contains only
single bonds, ethene with a double, and ethyne with a triple?
C2H6
C2H4
C2H2
sigma
Sigma + pi
Sigma + pi + pi
19. What type of bonds form in Ethane that contains only
single bonds, ethene with a double, and ethyne with a triple?
C2H6
C2H4
C2H2
sigma
Sigma + pi
Sigma + pi + pi
19. What type of bonds form in Ethane that contains only
single bonds, ethene with a double, and ethyne with a triple?
C2H6
C2H4
C2H2
sigma
Sigma + pi
Sigma + pi + pi
19. What type of bonds form in Ethane that contains only
single bonds, ethene with a double, and ethyne with a triple?
C2H6
C2H4
C2H2
sigma
Sigma + pi
Sigma + pi + pi