Chapter 11 - Liquids and Intermolecular Forces Flashcards
Define condensed phases.
solid and liquid states of matter
What is the fundamental difference between states of matter?
the strength of the intermolecular forces of attraction
List five characteristics of gas.
- assumes both volume and shape of its container
- expands to fill its container
- is compressible
- flows readily
- diffusion within a gas occurs rapidly
List five characteristics of liquid.
- assumes shape of portion of container it occupies
- does not expand to fill its container
- is virtually incompressible
- flows readily
- diffusion within a liquid occurs slowly
List five characteristics of solids.
- retains own shape and volume
- does not expand to fill its container
- is virtually incompressable
- does not flow
- diffusion within a solid occurs extremly slowly
How does kinetic energy compare to the energy of attraction for gas?
kinetic energies»_space; energies of attraction
How does kinetic energy compare to the energy of attraction for liquids?
comparable kinetic energies and energy of attraction
How does kinetic energy compare to the energy of attraction for solids?
energies of attraction»_space; kinetic energies
List five physical properties that reflect intermolecular forces.
boiling point, melting point, viscosity, surface tension, capillary action
The attractions between molecules are (stronger/weaker) then the intermolecular attractions that hold compounds together.
weaker
List the four types of molecular forces from strongest to weakest.
- dispersion forces
- dipole-dipole forces
- hydrogen bonding
- ion-dipole forces
What two types of intermolecular forces are referred to collectively as van der Waals forces?
dispersion forces, dipole-dipole forces
Which type of intermolecular force is a special type of dipole-dipole force?
hydrogen bonding
Define polarizability.
the tendency of an electron cloud to distort
What three factors affect the amount of dispersion force in a molecule?
- the number of electrons in an atom
- the size of the atom or molecule (molecular weight)
- shape of molecules with similar masses
How does the number of electrons in an atom affect the amount of dispersion force in a molecule?
more electrons = more dispersion force
How does the shape of molecules with similar masses affect the amount of dispersion force in a molecule?
more compact = less dispersion force
What is the relationship between polarizability and boiling point?
If something is easier to polarize, it has a lower boiling point. This means less intermolecular force.
Explain dipole-dipole interactions.
Polar molecules have a more positively charged end and a more negatively charged end, collectively referred to as a dipole. The oppositely charged ends attract each other.
On what molecules do dipole-dipole interactions have a greater effect then dispersion forces?
molecules of comparable side and shape
On what molecules do dispersion forces have a greater effect then dipole-dipole interactions?
molecules with significant differences in size
Define hydrogen bonds.
an attraction between a hydrogen atom attached to a highly electronegative atom and a nearby small electronegative atom in another molecule or chemical group
What is unusual about the dipole-dipole interactions when H is bonded to N, O, or F?
they are unusually stong
What forms hydrogen bonds?
Hydrogen bonding arises in part from the high electronegativity of nitrogen, oxygen, and flourine. These atoms interact with a nearly bare nucleus (which contains one proton).
