chem Flashcards
it states that matter is made up of particles that are constantly moving
kinetic molecular theory of solids and liquids
the arrangement of particles in solids, liquids, and gases explains the _
different properties
held by very strong forces of attraction, particle not free to move, particle vibrate about in fixed positions
solid (movement)
held together by strong forces of attraction, particles are able to slide past one another
liquid (movement)
very high density
solid
high density
liquid
extremely slowly infusibility
solid
slow infusibility
liquid
slighty compressible (solid and liquid)
compressibility
has fixed volume and shape
solid
assumes the shape of the container it occupies. has fixed volume
liquid
matter in the gas state
has indefinite shape and volume
matter in the _ state has indefinite shape and volume
gas
matter in the liquid state
has indefinite shape and definite volume
matter in the _ state has indefinite shape and definite volume
liquid
matter in the solid state
has definite shape and volume
matter in the _ state has definite shape and volume
solid
nobel prize for physics in 1910. norwegian dutch physicist. suggested that there must be a reason why gases condensed when cooled
Johannes Diderik van der Waals
sometimes called as noncovalent bonds
intermolecular forces
intermolecular forces sometimes called as
noncovalent bonds
Named after bonding, and London dispersion forces.
* Also Known as van der waals forces, named after a Dutch chemist, Johannes van der Waal (1837-1923).
intermolecular forces
are weak attractions that are used to explain the attraction between nonpolar molecules as it apparent that even nonpolar molecules can have dipoles for short periods of
time.
London Dispersion Forces (LDF)
LDF
London Dispersion Forces
the attraction of bond dipoles, in different molecules
dipole-dipole forces
exist when polar molecules are attracted to ions
ion-dipole forces
A weak bond formed when a hydrogen with partial positive charge is close to an atom in a molecule with lone pairs of electrons or with excess electronic charge.
hydrogen bond or hydrogen bridge
s the force that causes the molecules on the surface of a liquid to “tighten their hold to one another” creating the effect of a thin membrane on the surface.
surface tension
Substances with strong attractive forces between the molecules have high surface tensions.
surface tension
It is temperature-dependent; it decreases as temperature increases.
surface tension
is a measure of its tendency to resist flowing motion
viscosity
Polar molecules and molecules with complex structures tend to have higher viscosity, being less able to slip and slide over one another than those with simple structures and less polarty.
viscosity
the spontaneous rising of a liquid in a narrow tube, is also observed
capillary action
is much less in a liquid than in a gas, but it takes place at an easily measured rate ( it can slide over one another to effect diffusion)
diffusibility
another property of liquids
incompressibility
Since the molecules in a liquid are already close, touching one another, they cannot be crowded together anymore unless they are squeezed and deformed, which would require a great amount of energy.
incompressibility
is an indication of the escape of molecules from the surface of the liquid. It is an evidence of molecular motion.
evaporation
the molecules that escape from the surface of the liquid
cooling effect of evaporation
is the temperature at which the vapor pressure of a liquid is equal to the external pressure
boiling point
normal boiling point
760 mm Hg at sea level
when a liquid vaporizes in a closed container, the space above the liquid becomes saturated with vapor and an equilibrium state exist between the liquid and the vapor.
vapor pressure
expressed in cal/g or in kcal/g-atom or in kJ/kg, is the energy required to change exactly one gram of liquid to vapor at its normal boiling point
heat of vaporization
is a good solvent
water
has a high specific heat
water
the specific heat of water
1 calorie/g-˚C (4.18 J/g-˚C)
solids are generally classifies into:
amorphous or crystalline solids
means that the solid does not always adopt the same form
amorphous
its constituent particles are randomly arranged.
Do not have sharp melting point that is, melting within a narrow temperature range.
They soften first and melt little by little over a wide temperature range.
amorphous solid
A solid in which the constituent particles (atoms, ions, or molecules) have an orderly arrangement, that is, it has regularly arranged structure units with characteristics geometric forms.
Show regular shapes which reflect the arrangement of the particles within them.
crystalline solid
types of crystalline solids (4)
metallic crystals, ionic crystals, molecular crystals, covalent network crystals
have atoms arranged in an orderly repeating pattern
crystalline solids
lack the order found in crystalline solids
amorphous solids
are the simplest type of structure. can be thought of as three dimensional arrays of metal cations
metallic crystals
metallic crystals two choices
face centered cubic packing and hexagonal close-packing
Have ions as constituent particles.
This is exemplitied the sodium
chloride crystal.
The oppositely charged Na’ and CH
ions arrange themselves in a regular three-dimensional pattern of a crystal lattice.
ionic crystals
is the property shown by substances which have molecules or ions that
can assume more than one stable arrangement in the solid state.
polymorphism
The diferent molecular forms or various crystal modification of a polymorphous element are known as
allotropes
Those which have molecules as constituent particles as well as structure units.
Weak van der waals forces of attraction hold them together.
Solids like iodine, camphor, menthol and napthalene are recognized readily by their odor, an evidence that they are undergoing sublimation.
molecular crystals
Are giant molecules or macromolecules.
They consist of very large numbers of atoms linked by a network of covalent bonds.
These molecules may build up in one direction as long as chains which form fibrous crystals.
covalent network crystals
intermolecular forces of matter and properties of liquids (2)
surface tension and viscosity
other properties observed when matter is in the liquid phase (8)
capillary action, diffusibility, incompressibility, evaporation, cooling effect of evaporation, boiling point, vapor pressure, and heat of vaporization
is the temperature where vapor pressure equals atmospheric pressure
boiling point
intermolecular forces (4)
London Dispersion Forces, Dipole-Dipole Forces, Ion-Dipole Forces, Hydrogen Bond or Hydrogen Bridge
classes of solids (2)
amorphous solid and crystalline solid
consists of discrete regions that represent the different phases exhibited by a substance
typical phase diagram
is favored at low temperature and high pressure
solid phase
is favored at high temperature and low pressure
gas phase
is for a single pure substance in a closed system, not for a liquid in an open beaker in contact with air at 1 atm pressure.
phase diagram
correspond to the combinations of temperature and pressure at which two phases can coexist in equilibrium.
the lines in a phase diagram
Sublimation of water at low temperature and pressure can be used to _ foods and beverages.
“freeze-dry”
is emerging as a natural refrigerant, making it a low carbon (and thus a more environmentally friendly) solution for domestic heat pumps.
supercritical carbon dioxide
the graph of temperature against time is called a _
heating curve
show how the temperature changes as a substance is heated up
heating curves
they show how the temperature changes as a substance is cooled down. it have the horizontal flat parts where the state changes from gas to liquid
cooling curves
the _ ang _ occur at the same temperature
melting and freezing
during _, energy is removed and during _, energy is absorbed
freezing, melting
is a measure of average kinetic energy
temperature
temperature is a measure of _
average kinetic energy
any change in temperature is a change in _
kinetic energy
all the energy that is absorbed or released is related to changes in _
potential energy
3 Ps
plateau, phase change, and potential energy change
lesson 2
phase diagrams, heating and cooling curves
lesson 1
properties of solids and liquids to the nature of forces between particles