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46 terms

Liquids and Solids

intermolecular forces
hold molecules together with neighbors
weaker than chemical bonds
dispersion forces
between NONPOLAR molecules
dipole dipole forces
between polar molecules
hydrogen bonding
between polar molecules containing H-O, H-N, or H-F and a lone pair of electrons
what determines the type of bond
size, shape and polarity
what is significant about hydrogen bonding
what holds the 2 strands in DNA is purely hydrogen bonding
what does hydrogen bonding cause
high boiling point
what are dispersion forces caused by
temporary uneven charge distribution
temporary dipole
temporary dipole
Temporary/ instantaneous dipole - when the side of an electron is little bit negative and the other side is a little bit positive which allows the molecule to react for a short amount of time but it is not polar
intermolecular force properties of liquids
1. surface tension
2. wetting
3. capillary action
4. viscosity
surface tension
resistance of a liquid to an increase in surface area
causes breading of water droplets
strong IMF cause high surface tension
the spreading of liquid across a surface to form a thin film
IMF are roughly equal to liquid/surface attraction
capillary action
rising of liquid in a narrow tube
combination of cohesive IMF and adhesive forces
resistance to flow
large molecules are viscous
strong IMF cause high viscosity (harder to pour)
very regular microscopic arrangement
disordered microscopic structure
molecular solids
discrete molecules are at lattice positions
strong IMF
weak IMF
ionic solids
tightly packed ions are held together by strong electrostatic forces
larger anions arrange themselves
smaller cations fit into holes
changing from solid to liquid
changing from liquid to solid
chaning from gas to liquid
changing from liquid to gas
(evaporation or boiling)
below BP, only molecules with the highest kinetic energy leave from the surface of a liquid
what does the rate of vaporization depend on
1. surface area
2. temperature
3. IMF
what do closed containers of liquid establish
a dynamic equilibrium
dynamic equilibrium
two processes happening at the same rate
involves rates of vaporization and condensation that are equal
changing from solid to gas without going through liqid phase
changing from gas to solid without going through liquid phase
vapor pressure
a force created by vapor particles over liquid surface at equilibrium
when vapor pressure and atmospheric pressure are equal
the higher the temperature, the more energy particles they have so the more pressure they have
normal boiling point
occurs when vapor pressure is equal to 1 atm
when is boiling point reached
when vapor pressure equals atmospheric pressure while vapor pressure increase with increasing temperature
what is observed when heat energy is added to a sample
phase is observed while pressure is constant
what is constant during a phase change
triple point
point at which vapor, liquid, and solid states exist in equilibrium
critical point
point at which the vapor pressure line ends
critical temperature
temperature at critical point above which a distinct liquid phase cannot exist, regardless of pressure
what do IMF affect
physical properties of substances in condensed states
how are metals packed
tightly into regular arrays
how would you describe network solids
"Giant molecules" joined by IMF
what do molecular solids have
weak IMF
low BP and MP
what do ionic solids have
stronger IMF
higher BP and MP
packed together in regular arrays of anions and cations
how do phase changes occur
within changes in temperature and/or pressure
where does vapor pressure occur and what is it affected by
occurs at liquid surfaces and is affected by IMF
what do heating curves track
changed with temperature
what do phase diagrams track
changed with temperature and pressure