WHAT HOLDS SOLIDS and LIQUIDS Flashcards
- explains the properties of solids and liquids in terms of the intermolecular forces of attraction and the kinetic energy of the individual particles.
KINETIC MOLECULAR MODEL
attractive forces between neighboring particles of one or more substances
pull the particles together.
INTERMOLECULAR FORCES
keeps the particles at a distance and/or moving around.
dependent on the temperature of the substance.
KINETIC ENERGY
van der Waals Forces
Dipole-Dipole Force
Hydrogen Bonds
Ion-Dipole Forces
London Dispersion Forces
exist between polar molecules.
Dipole-Dipole Forces
is a special type of dipole-dipole interaction that exists only in molecules that contain a hydrogen atom bonded to a small, highly electronegative atom such as N, O, or F.
about 5-10 times stronger than other dipole-dipole attractions.
Hydrogen Bonds
Hydrogen bonding is an important intermolecular force that affects the physical properties of molecules.
true
Intermolecular forces of attraction influence the properties of solids and liquids
true
acts between an ion and a polar molecule.
Ion-Dipole Forces
are intermolecular forces of attraction that exist between all atoms and molecules.
The only force acting in nonpolar molecules.
London Dispersion Forces
a liquid takes a shape of the container because particles in a liquid can flow to new locations
the volume of a liquid is constant because forces of attraction keep the particles close together
the particles in a liquid are more closely packed than the particles in a gas. therefore attractions between them do affect the movement of a particle
BEHAVIOR OF LIQUIDS
GENERAL PROPERTIES OF LIQUIDS
surface tension
viscosity
vapor pressure
boiling point
heat of vaporization
is the property of a liquid to resist an external force and thus assume a lesser surface area.
manifestations:
- paperclip on the surface of water
- water forms beads on the leaves
- insects can walk on water
Surface Tension
The high surface tension of water is due to the strength of hydrogen bonding.
true
is the resistance of a liquid to flow.
the thickness or thinness of a liquid.
VISCOSITY
the pressure exerted by its vapor when in equilibrium with its liquid or solid.
VAPOR PRESSURE
the transformation of a substance from a liquid to gas.
is an endothermic process as it requires absorption of energy to break the intermolecular forces of attraction in a liquid.
Vaporization
The large heat of vaporization of water protects earth from warming brought about by the sun’s energy.
true
For liquids, the greater the intermolecular forces of attraction, the lower is the vapor pressure or tendency to evaporate.
true
the temperature at which its vapor pressure is equal to the external or atmospheric pressure
normal boiling point
(1 atm=760 mmHg) of water is
100oC.
stronger hydrogen bonding exists in water while weaker in hexane.
BOILING POINT
is the amount of heat required to vaporize one mole of a substance at its boiling point.
HEAT OF VAPORIZATION (∆Hvap)
solids have fixed locations and a lotal volume that doesn’t change
solids have a definite volume and shape because particles in a solid vibrate sound and fixed locations
each atom vibrates around its location but it does not exchange places with a neighboring atom
BEHAVIOR OF SOLIDS
TYPES OF SOLIDS
Amorphous Solids
Crystalline Solids
particles are not arranged in a paricular pattern
do not melt at specific temp
instead become gradually softer or change into another substance
do not have a definite melting point and can exist in two different states: rubbery or glassy state
e.g. candle wax, glass, chocolate/cheeses, rubber, butter
amorphous solids
regular, repeating pattern
a crystal is a solid that was slowly formed from one type of atom
we call this a pure substance
melts at distinct, characteristic melting point
example: iron, diamonds, ice, salt, snow, sugar, sand
crystalline solids
