Chemistry ch 17
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Chemistry ch 17
as the temperature of a solid increases, what else increases?
velocity of the particles
when are melting point and freezing point the same?
at the same pressure
particles slip out of their organized pattern and the solid becomes a liquid
particles of the liquid move so slowly that they move back into an organized pattern
particles move so fast that the liquid becomes vapor
that state in which 2 opposing processes occur at an equal rate
requires a closed system
particles are constantly moving from or returning to the liquid
when the liquid is in equilibrium with the vapor above it
the high the temperature, the higher the _____ gases exert
Le Chatelier's principle
when a system in equilibrium is stressed, the system will react to relieve the stress
change in temperature, pressure, and concentration
the pressure generated by a vapor that is in equilibrium with a liquid
Low vp has what kind of intermolecular forces?
strong- hold particles tightly
high vp has what kind of intermolecular forces
weak- hold particles weakly
melting point (solid)
the temp at which the vp of the solid and the vp of the liquid are equal
solids that vaporize quickly in air without going through the liquid phase
dry ice, moth balls
What happens when temperature rises in a lquid?
vp and ke also increase
molecules get pushed further apart
bubbles of vapor form and the move to the liqid's surface
the vp in a system is equal to the standard atmospheric pressure- 101.3 kPa
BP is a function of
the lower the air pressure, the lower the bp
what is the difference between boiling and evaporation?
evaporation occurs at the surface
boiling occurs throughout
boils at low temp and evaporates quickly at room temperature
boils at high temp and evaporates slowly at room temperature
what kind of vp's do volatile liquids have?
what kind of vp's do non-volatile liquids have?
condensing substances that are normally gases at room temp to liquids- involves temp and pressure
temp above which no amount of pressure will result in the liquefaction of a gas
the pressure that will cause a gas to liquefy at Tc
Low Tc indicates
weak forces between molecules
High Tc indicates
strong forces between between molecules
shows the relationship between temperature, pressure, and physical state
the temp and pressure at which all 3 phases are at equilibrium
when energy is added to a solid, the temp of the solid increases until
Tm is reached
the temperature of a melting solid doesn't change until
all of the solid is completely melted
What does the energy added to a solid need to change?
the position of the particles- PE is increased
enthalpy of fusion
the energy required to melt 1 gram of a substance at its Tm
^Hfus of ice
enthalpy of vaporization
the energy required to vaporize 1gram of a substance at its Tb
^Hvap of water
melting and boiling points for molecules can be predicted with a knowledge of
the atomic and molecular structure
melting and boiling points for molecules can be predicted with a knowledge of the atomic and molecular structures unless
the molecules contain H that is covalently bonded to a highly electronegative atom
highly polar molecule
hydrogen bonding forms?
extremely strong dipole
what does H bond with to form these dipoles?
N, O, F
NH3, H2O, HF
when is water most dense?
3.98 deg C
what breaks H bonds?
in ice, one molecule of water is bonded to ____ other water molecules
the clusers of hydrogen bonds in ice creat what?
many open spaces
surface tension is due to
the unbalanced forces on the surface particles of a liquid
what kind of surface tension does water have?
what kind of surface tension does mercury have?