Chapter 11 Intermolecular Forces Liquids and Solids

characteristics of a gas

assumes both the volume and shape of its container

is compressible

flows readily

diffusion within a gas occurs rapidly

characteristics of a liquid

assumes the shape of the portion of the container it occupies

does not extend to fill container

is virtually incompressible

flows readily

diffusion within a liquid occurs slowly

characteristics of a solid

retains its own shape and volume

is virtually incompressible and does not flow readily. Diffusion within a solid occurs extremely slowly.

condensed phases

in the solid and liquid states particles are closer together

intermolecular forces

forces that exist between molecules and are much weaker than normal ionic and covalent bonds

van der waals forces

intermolecular forces as a group

type of van der waals forces

dipole dipole interactions

hydrogen bonding

london dispersion forces

ion dipole forces

forces that exist between an ion and a polar molecule

dipole dipole interactions

forces that exist between polar molecules

viscosity

a measure of liquid’s resistance to flow

increased with increase in strength of intermolecular forces and decreases with increase in temperature

ex. oil, honey, water

larger molecules

have higher viscosities because attractive forces between molecules are higher

surface tension

the energy require to spread a liquid on a surface by a unit amount

cohesive forces

intermolecular forces that bind to smaller molecular forces

adhesive forces

intermolecular forces that bind a substance to a surface

meniscus of water

is u-shaped because the forces between water molecules and glass are stronger than between water molecules

meniscus of mercury

is curved downward because forces between mercury atoms are stronger than forces between mercury and glass

capillary action

the ability of a liquid to flow against gravity up a narrow tube

phase change

the transformation of the three states of matter from one state to another

can be summarized by a heating curve

heat of vaporization

is defined as the energy required to change a liquid at its boiling point to a gas

heat of fusion

is defined as the energy required to change a solid at its melting point to a liquid

heating curves

are graphs used to calculate energy changes that accompany phase changes

what happens when heated is added during phase change?

the heat added to the system at the melting and boiling points goes into pulling the molecules farther apart from each other

critical temperature

is the highest temperature at which a substance can exist as a liquid

critical pressure

is the pressure required for liquification of a gas at the critical temperature

vapor pressure of a liquid

is the pressure exerted by its vapor when the liquid and the vapor are in dynamic equilibrium

rate of gas molecules condensing equals

rate of liquid molecules evaporating

volatile liquids

liquids that evaporate easily

normal boiling point

the boiling point of 1 atm (760mmHg)