Ch 10 Section 1 Flashcards
scientists developed the kinetic-molecular theory of matter to account for the
behavior of the atoms and molecules that make up matter
the kinetic-molecular theory is based on the idea that particles of matter are
always in motion
the kinetic-molecular theory can be used to explain the properties of solids, liquids, and gases in terms of the
energy of particles and the forces that act between them
the kinetic-molecular theory can help you understand the behavior of gas
molecules and the physical properties of gases
the theory provides a model of what is called an
ideal gas
an ideal gas is a hypothetical gas that perfectly fits all the assumptions of the
kinetic-molecular theory
(5 assumptions of the kinetic-molecular theory) gases consist of large numbers of tiny particles that are
far apart relative to their size
(5 assumptions of the kinetic-molecular theory) these particles, usually molecules or atoms, typically occupy a volume that is about 1000 times greater than the
volume occupied by an equal number of particles in the liquid or solid state
(5 assumptions of the kinetic-molecular theory) molecules of gases are much farther apart than molecules of
liquids or solids
(5 assumptions of the kinetic-molecular theory) most of the volume occupied by a gas is empty space, which is the reason that gases have a
lower density than liquids and solids do (explains that gases are easily compressed)
(5 assumptions of the kinetic-molecular theory) collisions between gas particles and between particles and container walls are
elastic collisions
(5 assumptions of the kinetic-molecular theory) an elastic collision is one in which there is no net loss of
total kinetic energy
(5 assumptions of the kinetic-molecular theory) kinetic energy is transferred between two particles during
collisions
(5 assumptions of the kinetic-molecular theory) however, the total kinetic energy of the two particles remains the same as long as
temperature is constant
(5 assumptions of the kinetic-molecular theory) gas particles are in continuous,
rapid, random motion
(5 assumptions of the kinetic-molecular theory) since gas particles are in continuous, rapid, random motion they possess
kinetic energy, which is energy of motion
(5 assumptions of the kinetic-molecular theory) gas particles move in all
directions
(5 assumptions of the kinetic-molecular theory) the kinetic energy of the gas particles overcomes the attractive forces between them, except near the
temperature at which the gas condenses and becomes a liquid
(5 assumptions of the kinetic-molecular theory) there are no forces of…..gas particles
attraction between
(5 assumptions of the kinetic-molecular theory) the temperature of a gas depends on the average
kinetic energy of the particles of the gas
(5 assumptions of the kinetic-molecular theory) the kinetic energy of any moving object, including a particle, is given by the following equation:
KE= 1/2 mv²
(5 assumptions of the kinetic-molecular theory) in the equation, m is the
mass of the particle and v is its speed
because all the particles of a specific gas have the same mass, their kinetic energies depend only on
their speeds
the average speeds and kinetic energies of gas particles increase with an increase in …. and decrease with a decrease in….
temperature, temperature
all gases at the same temperature have the same
average kinetic energy
at the same temperature, lighter gas particles (like hydrogen molecules) have higher average speeds than do
heavier gas particles, such as oxygen molecules
although ideal gases do not actually exist, many gases behave nearly ideally if pressure is not very
high and temperature is not very low
gases do not have a definite
shape or a definite volume
gases completely fill any container in which they are
enclosed, and they take its shape
the fact that gases fill any container and take its shape is explained by the assumptions that gas particles move
rapidly in all directions without significant attraction between them
because the attractive forces between gas particles are insignificant (assumption 4) gas particles glide easily
past one another
this ability to flow causes gases to behave as
liquids do
because liquids and gases flow, they are both referred to as
fluids
the density of a gaseous substance at atmospheric pressure is about ….the density of the same substance in the…
1/1000; liquid or solid state
the reason that the density of a gas is lower than in the other states is that the particles are so much farther apart in the
gaseous state (assumption 1)
during compression, the gas particles, which are initially very far apart (assumption 1), are
crowded closer together
the volume of a given sample of a gas can be greatly
decreased
steel cylinders containing gases under pressure are widely
used in industry
when they are full, such cylinders may contain more than 100 times as many particles of gas as
nonpressurized containers of the same size could contain
gases spread out and mix with one another, even without being
stirred
diffusion is the spontaneous mixing of the …. of two substances caused by their
particles; random motion
gases diffuse readily into one another and mix together due to the rapid motion of the molecules and the
empty space between the molecules
effusion is a process by which gas particles pass through a
tiny opening
the rates of effusion of different gases are directly proportional to the
velocities of their particles
because of this proportionality, molecules of low mass effuse…than molecules of high mass
faster
because particles of gases occupy space and exert attractive forces on each other, all real gases deviate to some degree from
ideal gas behavior
a real gas is a gas that does not behave completely, according to the
assumptions of the kinetic-molecular theory
at very high pressures and low temperatures, the gas particles will be closer together and their kinetic energy will be insufficient to
overcome completely the attractive forces
at such conditions, the gas is most likely to behave like a
non-ideal gas
the kinetic-molecular theory is more likely to hold true for gases whose particles have little
attraction for each other
the noble gases show essentially ideal gas behavior over a wide range of
temperatures and pressures
the particles of noble gases are monatomic and thus
nonpolar
the particles of gases, such as nitrogen and hydrogen, are nonpolar
diatomic molecules
the behavior of these molecules (diatomic) most closely approximates that of the
ideal gas under certain conditions
the more polar the molecules of a gas are, the greater the attractive forces between them and the more the gas will
deviate from ideal gas behavior
highly polar gases deviate from ideal behavior to a larger degree than
nonpolar gases
