test 11 Flashcards
name the 3 types of intermolecular forces
- dipole-dipole force
- hydrogen bonds
- dispersion forces
an intermolecular force; the attraction of the positive end of one polar molecule to the negative end of another polar molecule
dipole-dipole force
a special dipole-dipole force involving hydrogen and a highly electronegative element
hydrogen bonds
when bonded with hydrogen which highly electronegative elements cause the shared electrons to shift away from the hydrogen atoms, because of their greater electronegativity?
fluorine, oxygen, or nitrogen.
which intermolecular force is the strongest and why?
hydrogen bonds. the combination of a high polarity and proximity produces the strongest
a substance is typically about________ denser as a solid than as a liquid and what is the exception?
10% and water
completely describe what happens as water’s temperature drops.
down to a temperature of 4*C, water becomes increasingly dense, but as it cools below this temperature, hydrogen bonds and dipole-dipole forces cause water molecules to spread apart from each other, assembling into an open hexagonal lattice. increased space between the molecules causes ice to be less dense than water, which makes it float
ionic and metallic solids are usually___________
crystalline
give 5 examples of amorphous solids
- rubber
- some plastics
- asphalt
- paraffin
- amorphous sulfur
the temperature at which a substance changes between the solid and liquid states is called what?
melting point
what is the transformation from a solid to a liquid?
melting
crystalline substance have _________melting points
distinct
the direct change in state from the solid to the gaseous state
sublimation
what are the 7 basic crystals
- cubic
- tetreagonal
- rhombohedral
- triclinic
- monoclinic
- hexagonal
- orthorhombic
elements or compounds that can form more than one type of crystal lattice are called what
polymorphous
the ———– of a crystal is the energy released when gaseous particles form crystals
lattice energy
the magnitude of the electrical charges in a crystal affects its ——
stability
why does particle size affect binding forces
small particles can be more tightly bound than large particles
the ———– of a crystal also affects the binding forces
geometric structure
what affects the strength of a crystal
size of particles
geometric structure
the charges of the particles
a substance that is added to a liquid that acts to reduce the surface tension of that liquid by interfering with hydrogen bonds
surfactants
a liquid’s ability to resist flowing
viscosity
the reverse of vaporization- it is the formation of a liquid from its gaseous state
condensation
evaporation is a ——— process
cooling
what type of attractions allow quick evaporation
weak
when the two processes of condensation and evaporation balance each other so that no net effect can be observed
dynamic equilibrium
the temperature at which the vapor pressure equals the applied pressure
boiling point
what can condense and even solidify any gas
low temperatures and high pressures
the highest temperature at which a gas can be liquified
critical temperature (Tc)
when would most evaporation occur
high temps
what affects evaporation
temperature and molecular attraction
a solid in which the particles occur in random positions with no orderly pattern. Examples include asphalt and paraffin
amorphous solid
a state of matter in which the particles have relatively little energy, cannot overcome the attractive forces, and remain in fixed positions with set distances between them. It has fixed a volume and is relatively incompressible
solid
the basic building block for any type of crystal; the section of a crystal lattice that contains one formula unit of the compound or one repeating segment of the overall lattice strucure
unit cell
one of two or more forms of a polymorphous element that exists in the same physical state
allotropes
the curved upper surface of a column of liquid that results from intermolecular attractions within the liquid and between the liquid and its container
meniscus
the movement of a liquid up a narrow tube caused by adhesion between molecules in the walls of the tube and the molecules of the liquid
capillary action
a general term for a physical change from the liquid state to the vapor or gaseous state
vaporization
a physical change from the liquid state to the gaseous state that occurs at the surface of a liquid when the temperature is between the substance’s freezing and boiling points
evaporation
when pressure is exerted by a vapor in equilibrium its solid or liquid state at a specified temperature
vapor pressure
a technique used to separate a mixture by evaporating its components at their boiling points and then condensing and collecting the vapors
distillation
3 types of vaporization
evaporation
boiling
condensation
