chapter 08 part 1_kinetic_model_of_matter
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Chapter 08 Part 1Chapter 08 Part 1Kinetic Model Of Matter
What is the smallest building What is the smallest building block of matter?block of matter?For this course, the
smallest building block is◦an atom(element)◦a
molecule(compound)
What is this model?What is this model?
The Kinetic Model of Matter states that:
matter are composed of a large number of small particles (i.e. atoms, molecules)
individual particles are in constant motion.
3 states of matter3 states of matterSolid
◦Fixed shape and volume◦Normally hard & rigid; a large force
is needed to change its shape◦High density◦Incompressible
3 states of matter3 states of matterLiquid
◦Fixed volume but does not have a fixed shape
◦High density◦Incompressible
3 states of matter3 states of matterGas
◦No fixed shape or volume◦Low density◦Compressible
3 states of matter with the 3 states of matter with the kinetic model of matter kinetic model of matter gives…gives…The kinetic model of matter
3 states of matter explained 3 states of matter explained using the kinetic model of using the kinetic model of matter: matter: SolidSolid
Arrangement of particles◦ Closely packed
together◦ Usually in a
regular pattern◦ Occupying
minimum space◦ Results in solids
having high densities
Movement of particles◦ Vibrate about fixed
positions only.◦ Held by very strong
intermolecular bonds.
◦ This explains why solids have fixed volumes and shapes.
3 states of matter explained 3 states of matter explained using the kinetic model of using the kinetic model of matter: matter: LiquidLiquid
Arrangement of particles◦ Randomly arranged◦ Particles are
slightly further apart as compared to solids
◦ Results in liquids having relatively high densities (generally less dense than solids)
Movement of particles◦ Free to move about
but confined within the vessel containing it.
◦ Have attractive forces between particles.
◦ This explains why liquids have fixed volumes but will take the shape of the vessels containing them.
3 states of matter explained 3 states of matter explained using the kinetic model of using the kinetic model of matter: matter: GasGasArrangement
of particles◦ Randomly
arranged◦ Particles are very
far apart◦ Occupy any
available space.◦ Results in gases
having very low densities
Movement of particles◦ Move about
randomly, freely and at high speeds
◦ Have very little attractive forces between particles.
◦ This explains why gases have no fixed volume and shape, and why they are highly compressible.
3 states of matter explained 3 states of matter explained using the kinetic model of using the kinetic model of mattermatter
Evidence to support the Evidence to support the kinetic model of matterkinetic model of matterThe size of atoms/molecules are
very small.Nobody has ever seen an atom or
a molecule before.How do we know that the kinetic
model of matter is correct?◦The observation of Brownian motion
Brownian motionBrownian motionThe random or irregular motion of microscopic particles suspended in fluids due to the uneven bombardment of the suspended particles by the molecules of the fluid is called Brownian motion.◦Occurs only in fluids.
The setup to observed The setup to observed Brownian motionBrownian motion
Why do the smoke particles Why do the smoke particles move irregularly and move irregularly and haphazardly?haphazardly?The smoke particles, being
much larger than the air molecules, are continually bombarded unevenly from different sides by the surrounding air molecules.
Smoke particle
Air molecule
Effects of temperature on Effects of temperature on molecular motionmolecular motionThe Brownian motion of smoke
particles at higher temperature will be more vigorous and agitated.
Why??◦As temperature increases, a larger
amount of thermal energy is converted to kinetic energy of the air molecules.
◦Causes the air molecules to move at higher speeds.
◦Thus, the air molecules will bombard the smoke particles more vigorously and frequently.
◦Causing the Brownian motion of the smoke particles to be more vigorous and agitated.