The Kinetic Molecular Model of Matter Flashcards
What is the smallest building block of matter?
For this course, the smallest building block is
an atom(element)
a molecule(compound
matter are composed of a large number of small particles (i.e. atoms, molecules)
individual particles are in constant motion.
The Kinetic Model of Matter
Fixed shape and volume
Normally hard & rigid; a large force is needed to change its shape
High density
Incompressible
solid
Fixed volume but does not have a fixed shape
High density
Incompressible
liquid
No fixed shape or volume
Low density
Compressible
gas
Arrangement of particles:
Closely packed together
Usually in a regular pattern
Occupying minimum space
Results in solids having high densities
solid
Movement of particles:
Vibrate about fixed positions only.
Held by very strong intermolecular bonds.
This explains why solids have fixed volumes and shapes.
solid
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)
liquids
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.
liquid
Arrangement of particles:
Randomly arranged
Particles are very far apart
Occupy any available space.
Results in gases having very low densities
gas
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.
gas
3 states of matter explained using the kinetic model of matter
strength of intermolecular force
weakest - gas
strongest - solid
relative distance between particles
close together - solid
far apart - gas
How do we know that the kinetic model of matter is correct?
The observation of Brownian motion
The 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
Occurs only in fluids.
Brownian motion
Why do the smoke particles move irregularly and haphazardly?
The smoke particles, being much larger than the air molecules, are continually bombarded unevenly from different sides by the surrounding air molecules.
Effects of temperature on molecular motion
The 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.
