Ch 10 Section 2 Flashcards
liquids are the least common state of
matter in the universe
liquids are less common than solids and gases because a substance can exist in the liquid state only within a r
relatively narrow range of temperatures and pressures
a liquid can be described as a form of matter tha has a definite volume and
takes the shape of its container
the properties of liquids can be undrstood by applying the kinetic-molecular theory, considering the
motion and arrangement of molecules and the attractive forces between them
particles in a liquid are in
constant motion
the particles in a liquid are closer together than the particles in a
gas are
the attractive forces between particles in a liquid are more effective than those between
particles in a gas
this attraction between liquid particles is caused by
intermolecular forces: dipole-dipole, London dispersion forces, and hydrogen bonding
some molecules at the surface of a liquid can have enough kinetic energy to overcome these forces and
enter the gas state
liquids are more ordered than gases because of the stronger intermolecular forces and the lower
mobility of the liquid particles
according to the kinetic-molecular theory of liquids, the particles are not
bound together in fixed position. they move about constantly (explains why liquids & gases are fluids)
fluid is a substance that can flow and therefore
take the shape of its container
most liquids naturally flow downhill because of
gravity
some liquids can flow in other
directions as well
at normal atmospheric pressure, most substances are hundreds of times denser in a liquid state than in a
gaseous tate
this higher density is a result of the close arrangement of
liquid particles
most substances are only slightly less dense (about 10%) in a liquid state than in a
solid state
water is one of the few substances that becomes less
dense when it solidifies
at the same temperature and pressure, different liquids can
differ greatly in densithy
when liquid water at 20 degrees celsius is compressed by a pressure of 1000 atm, its volume decreases by only
4%→behavior is typical of all liqudis and similar to behavior of solids
a gas under pressure of 1000 atm would have only 1/1000 of its volume at
normal atmospheric pressure
liquids are much less compressible than gases because liquid particles are
more closely packed together
like gases, liquids can transmit
pressure equally in all directions
liquids also diffuse and mix with other
liquids
any liquid gradually diffuses throughout any other liquid in which it
can dissolve
the constant, random motion of particles causes diffusion in liquids, as it does in
gases
yet diffusion is much slower in liquids because liquid particles are
closer together
theh attractive forces between the particles of a liquid
slow their movement
as the temperature of a liquid is increased, diffusion occurs more
rapidly
the reason is that average kinetic energy, and therefore the average speed of the particles, is
incresaed
a property common to all liquids is surface tension: a forced that tends to pull adjacent parts of a liquid’s surface together, thereby decreasing
surface area to the smallest possible size
surface tension results from the attractive forces between
particles of a liqudi
the higher the force of attraction, the higher the
surface tension
water has a higher surface tension than most liquids because of the hydrogen bonds water molecules can
form with each other
the molecules at the surface of the water can form hydrogen bonds with the other water molecules beneath them and beside them, but not with
the molecules in the air above them
the surface water molecules are drawn togethyer and toward the body of the liquid, creating a
high surface tension
surface tension causes liquid droplets to take on a spherical shape because a sphere has the smallest possible
surface area for a given volume
capillary action, the attraction of the surface of a
liquid to the surface of a solid
capillary action is a property closely related to
surface tension
a liquid will rise quite high in a very narrow tube and will wet the tube if a strong attraction exists between the liquid molecules and the molecules that make up the
surface of the tube
this attraction tends to pull the liquid molecules upward along the surface and against the
pull of gravity
this process continues until the attractive forces between the liquid molecules and the surface of the tube are
balanced by the weight of the liquid
capillary action can occur between
water molecules and paper fibers
capillary action is at least partly responsible for the transportation of water from the roots of a plant to its
leaves t
capillary action is also responsible for the concave liquid surface, called a meniscus, that forms in a
test tube or graduated cylinder
the process by which a liquid or solid changes to a gas is
vaporization
evaporation is the process by which particles escape from the surface of a
nonboiling liquid and enter the gas state
evaporation occurs because the particles of a liquid have different
kinetic energies
particles with higher-than-average energies move
faster
some surface particles with higher-than-average energies can overcome the
intermolecular forces that bind them to the liquid and can then escape into the gas state
evaporation removes fresh water from the surface of the ocean, leaving behind a heigher
concentration of salts
boiling is the change of a liquid to bubbles of vapor that appear
throughout the liquid
when a liquid is cooled, the average energy of its particles
decreases
if the energy is low enough, attractive forces pull the particles into an even more
orderly arrangement
the physical change of a liquid to a solid by removal of energy as heat is called
freezing or solidification
all liquids freeze, although not necessarily at temperatures you
normally encounter
