Chemistry Chapter 11 Liquid, Solids, and
Intermolecular Forces
Sec 11.1: Climbing Geckos and Intermolecular Forces:
Intermolecular Forces-attractive forces that exist between all molecules and atoms, the
forces that hold many liquids and solids together
*Note: the state of a sample matter (solid liquid or gas) depends on the magnitude of
intermolecular forces between the constituent particles relative to the amount of
thermal energy in the sample
Sec 11.2: Solids, Liquids, and Gases: A Molecular Comparison:
Crystalline-the atoms or molecules that compose a solid are arranged in a well-
ordered 3D way
Amorphous-the atoms or molecules that compose a solid have no long-range order,
they are “disordered”
*Note: pressure, temperature or both can change the state of matter
Sec 11.3: Intermolecular Forces: The Forces that Hold Condensed States
Together:
Dispersion Force- the one intermolecular force that is present in all molecules and
atoms, it is the result of fluctuations in the electron distribution within molecules or
atoms
*Note: The magnitude of the dispersion depends on how easily an electron in the atom
or molecule can move in response to an dipole. That depends on the size of the electron
cloud. The size of the electron cloud can be estimated by looking at the molar mass of
the substance. It is important to note that a small electron cloud will result in a smaller
diversion force because the electrons are closer to the nucleus resulting in it being
harder for them to become polarized. To predict the magnitude of the diversion force
for closely related molecules and compounds, you would look at the shape. Molecules
that are long have more surface area to volume than molecules that are not. This
results in there being more places on the long molecule for things to interact with it.
Dipole-Dipole Force-the positive end of one permanent dipole attracts the negative end
of another; this exists in all polar molecules
*Note: To predict the presence of a dipole-dipole force in a compound you would simply
look to see if the molecule is polar or not. If it is polar, than there must be a dipole-
dipole force
Miscibility- the ability to mix without separating into two states; like the layers when
you mix oil and water are not miscible
, *Note: polar liquids are miscible with other polar liquids but are not miscible with
nonpolar liquids
Hydrogen Bonding-polar molecules containing hydrogen atoms boned directly to small
electronegative atoms (fluorine, oxygen, or nitrogen) exhibit this intermolecular force
Hydrogen Bond- is a like a super dipole-dipole force, a strong attraction between the H
atom on one molecule and the F, O, or N on its neighbor
Ion-Dipole Force-occurs when an ionic compound is mixed with a polar compound, it is
especially important in aqueous solutions of ionic compounds
Summary of Intermolecular Forces-
Page 495 Figure 11.4
Sec 11.4: Intermolecular Forces in Action: Surface Tension, Viscosity, and
Capillary Action:
Surface Tension- the energy required to increase the surface area by a unit amount of a
liquid
*Note: a molecule at the surface has relatively fewer neighbors with which to interact,
and it is therefor inherently less stable (it has higher potential energy) than those in
the interior
Viscosity-the resistance of a liquid to flow
*Note: viscosity is greater in substances with stronger intermolecular forces because if
molecules are more strongly attracted to each other, they do not flow around each
other as freely
Capillary Action-the ability of a liquid to flow against gravity up a narrow tube
*Note: capillary action results from a combination of two forces (Cohesive Forces and
Adhesive Forces)
Cohesive Forces-the attraction between molecules in a liquid, cause the liquid to stay
together
Adhesive Forces-the attraction between molecules and the surface of the tube, caused
the liquid to spread out over the surface of the tube
*Note: If the adhesive forces are greater than the cohesive forces, the attraction to the
surface draws the liquid up the tube and the cohesive forces pull along those molecules
not in direct contact with the tube walls
Sec 11.5: Vaporization and Vapor Pressure:
Vaporization- the transition from a liquid to a gas
Condensation- the transition from a gas to a liquid
Volatile-liquids that vaporize easily
Intermolecular Forces
Sec 11.1: Climbing Geckos and Intermolecular Forces:
Intermolecular Forces-attractive forces that exist between all molecules and atoms, the
forces that hold many liquids and solids together
*Note: the state of a sample matter (solid liquid or gas) depends on the magnitude of
intermolecular forces between the constituent particles relative to the amount of
thermal energy in the sample
Sec 11.2: Solids, Liquids, and Gases: A Molecular Comparison:
Crystalline-the atoms or molecules that compose a solid are arranged in a well-
ordered 3D way
Amorphous-the atoms or molecules that compose a solid have no long-range order,
they are “disordered”
*Note: pressure, temperature or both can change the state of matter
Sec 11.3: Intermolecular Forces: The Forces that Hold Condensed States
Together:
Dispersion Force- the one intermolecular force that is present in all molecules and
atoms, it is the result of fluctuations in the electron distribution within molecules or
atoms
*Note: The magnitude of the dispersion depends on how easily an electron in the atom
or molecule can move in response to an dipole. That depends on the size of the electron
cloud. The size of the electron cloud can be estimated by looking at the molar mass of
the substance. It is important to note that a small electron cloud will result in a smaller
diversion force because the electrons are closer to the nucleus resulting in it being
harder for them to become polarized. To predict the magnitude of the diversion force
for closely related molecules and compounds, you would look at the shape. Molecules
that are long have more surface area to volume than molecules that are not. This
results in there being more places on the long molecule for things to interact with it.
Dipole-Dipole Force-the positive end of one permanent dipole attracts the negative end
of another; this exists in all polar molecules
*Note: To predict the presence of a dipole-dipole force in a compound you would simply
look to see if the molecule is polar or not. If it is polar, than there must be a dipole-
dipole force
Miscibility- the ability to mix without separating into two states; like the layers when
you mix oil and water are not miscible
, *Note: polar liquids are miscible with other polar liquids but are not miscible with
nonpolar liquids
Hydrogen Bonding-polar molecules containing hydrogen atoms boned directly to small
electronegative atoms (fluorine, oxygen, or nitrogen) exhibit this intermolecular force
Hydrogen Bond- is a like a super dipole-dipole force, a strong attraction between the H
atom on one molecule and the F, O, or N on its neighbor
Ion-Dipole Force-occurs when an ionic compound is mixed with a polar compound, it is
especially important in aqueous solutions of ionic compounds
Summary of Intermolecular Forces-
Page 495 Figure 11.4
Sec 11.4: Intermolecular Forces in Action: Surface Tension, Viscosity, and
Capillary Action:
Surface Tension- the energy required to increase the surface area by a unit amount of a
liquid
*Note: a molecule at the surface has relatively fewer neighbors with which to interact,
and it is therefor inherently less stable (it has higher potential energy) than those in
the interior
Viscosity-the resistance of a liquid to flow
*Note: viscosity is greater in substances with stronger intermolecular forces because if
molecules are more strongly attracted to each other, they do not flow around each
other as freely
Capillary Action-the ability of a liquid to flow against gravity up a narrow tube
*Note: capillary action results from a combination of two forces (Cohesive Forces and
Adhesive Forces)
Cohesive Forces-the attraction between molecules in a liquid, cause the liquid to stay
together
Adhesive Forces-the attraction between molecules and the surface of the tube, caused
the liquid to spread out over the surface of the tube
*Note: If the adhesive forces are greater than the cohesive forces, the attraction to the
surface draws the liquid up the tube and the cohesive forces pull along those molecules
not in direct contact with the tube walls
Sec 11.5: Vaporization and Vapor Pressure:
Vaporization- the transition from a liquid to a gas
Condensation- the transition from a gas to a liquid
Volatile-liquids that vaporize easily
