unit 3 vocab Flashcards
pressure
the amount of force per unit area. F/A
barometer
an evacuated glass tube, the tip of which is submerged in a pool of mercury. used to measure pressure
torr
a millimeter of mercury (Hg)
manometer
u-shaped tube containing a dense liquid, usually mercury. used to measure the pressure of a sample relative to atmospheric pressure
boyle’s law
volume is proportional to 1 divided by pressure
charles’ law
volume is proportional to temperature
avogadro’s law
volume is proportional to number of moles
ideal gas law
PV=nRT
ideal gas
hypothetical gas that exactly follows the ideal gas law
molar volume of an ideal gas at STP
22.4 L
STP
standard temperature and pressure
partial pressure
the pressure due to any individual component in a gas mixture (Pn)
mole fraction
the number of moles of a component in a mixture divided by the total number of moles in the mixture
vapor pressure
the partial pressure of water vapor in a gas from the gas collection process after a chemical reaction
dalton’s law
the total pressure of a gas mixture is the sum of the partial pressures of its components
kinetic molecular theory
- particles are negligibly small in volume but have mass
- the average kinetic energy of a particle is proportional to the temperature in kelvins, atom’s motion is due to thermal energy
kinetic molecular theory
- particles are negligibly small in volume but have mass
- the average kinetic energy of a particle is proportional to the temperature in kelvins, atom’s motion is due to thermal energy
- when particles collide, there’s no loss of energy
mean free path
the average distance that a molecule travels in between collisions. increases as pressure decreases
diffusion
the process by which gas molecules spread out in response to a concentration gradient. influenced by the root mean square velocity
effusion
the process by which a gas escapes from a container into a vacuum through a small hole
graham’s law of effusion
rate A/rate B = square root of MB/MA
amorphous
a solid in which the atoms don’t have an sort of long-range order
miscibility
a liquid’s ability to mix without separating into two states
surface tension
the energy required to increase the surface area of a liquid by a unit amount. decreases as intermolecular forces decrease
viscosity
a measure of the resistance of a liquid to flow. increases with molar mass
poise (P)
unit used to measure viscosity, 1g/cm*s
capillary action
the ability of a liquid to flow against gravity up a narrow tube due to adhesive and cohesive forces
cohesive forces
attraction between molecules in a liquid. wants to hold together
adhesive forces
attraction between molecules and the surface of the tube. wants to spread out
volatile
vaporizes easily
sublimation
solid -> gas
vaporization
liquid-> gas
melting/fusion
solid-> liquid
deposition
gas -> solid
condensation
gas -> liquid
freezing
liquid -> solid
supercooling
when a liquid is cooled below the freezing point but remains liquid
boiling point
temperature where the vapor pressure of a liquid exceeds external pressure
normal boiling point
temperature when the vapor pressure equals 1atm
critical temperature (Tc)
temperature where a liquid can’t exist, regardless of pressure
critical pressure (Pc)
pressure required to bring about a transition to a liquid at Tc
heat of fusion
the amount of heat required to melt 1 mol of a solid
heat of sublimation
amount of heat required to sublime 1 mol of a solid to gas. sum of heat of fusion + heat of vaporization
phase diagram
a map of the state or phase of a substance as a function of pressure (y axis) and temp (x axis)
triple point
unique set of conditions where all three phases of a substance are equally stable and in equilibrium
solution
homogeneous mixture of two substances
solvent
majority component of a solution
solubility
amount of a substance that will dissolve in a given amount of solvent
entropy
a measure of the energy randomization or energy dispersal in a system
miscible
the ability of two or more substances to be soluble in each other in all proportions
enthalpy of solution
the enthalpy change associated with the formation of a solution
heat of hydration
the energy change that occurs when 1 mol of gaseous solute ions is dissolved in water
semipermeable membrane
membrane that selectively allows some things to permeate but not others
osmotic pressure
pressure required to stop osmotic flow
dynamic equilibrium
the point at which the rate of the reverse reaction or process equals the rate of the forward reaction or process
saturated solution
solution in which the dissolved solute is in dynamic equilibrium with any undissolved solute
unsaturated solution
solution with less than the equilibrium amount of solute
supersaturated solution
unstable solution with more than the equilibrium amount of solute dissolved
recrystallization
common way to purify a solid
dilute solution
contains a very small amount of solute vs. solvent
molarity (M)
moles of solute per L of solution
molality (m)
moles of solute per kg of solvent
colligative property
a property that depends on the amount of solute but not the type
vapor pressure lowering
the change in vapor pressure that occurs in pure substances upon addition of a solute. directly proportional to the mole fraction of the solute
ideal solution
solute and solvent follow Raoult’s Law at all concentrations
freezing point depression
effect of a solute that causes a solution to have a lower melting point than the pure solvent
boiling point elevation
effect of a solute that causes a solution to have a higher boiling point than the pure solvent
osmosis
flow of a solvent of of lower solute concentration to a solution of higher solute concentration
van’t hoff factor
ratio of moles of particles in a solution to moles of formula units dissolved
colloidal dispersion (colloid)
a mixture in which a dispersed substance is finely dived but not truly dissolved in a dispersing medium. ex. fog, smoke, milk