Final/Unit 4 Flashcards
Amonton’s Law
Relationship between gas pressure and temperature
Directly proportional
P=kT
Charles’ Law
Relationship between gas volume and temperature
Directly proportional
V=kT
Boule’s Law
Relationship between gas volume and pressure
Inversely proportional
V=k/P
Avogadro’s Law
Relationship between gas volume and amount
Directly proportional
V=kn
Ideal Gas Law
Equation and units
PV=nRT
P = pressure in atm
V = volume in L
n = amount in mol
R = gas constant (Latm)/(molK)
T = temperature in K
Requirements of an ideal gas
5 assumptions, 2 likely to be broken
- molecules act like hard spheres
- no energy lost in collisions
**3. volume occupied by gas is negligable compared to container volume - negligable IMFs between the molecules**
- KE depends only on temperature
Conditions that break ideal gas assumptions
2 answers
- high pressure
- low temperature
3 types of IMFs (intermolecular forces)
in order of weakest to strongest
- dispersion forces
- dipole-dipole interactions
- hydrogen bonding
Dispersion forces
definition, qualifications
Instantaneous dipole caused by random electron distribution induces a dipole between molecules.
Applies to all substances
Attributes that cause stronger dispersion forces
2 answers
Heavier MW (more e-)
Bigger surface area (more contact)
Dipole-dipole interactions
definition, qualifications
Polar molecules interact through partial charge attractions
Requires a polar molecule
Attributes that cause stronger dipole-dipole interactions
1 answer
Larger electronegativity difference between the atoms
Hydrogen bonding
definition, qualifications
Unusually strong form of dipole-dipole
Requires covalent bond between H and N, O, or F
Viscosity
definition, relationship to IMFs
the resistence of a substance to flowing
stronger IMFs = more viscous
Cohesion
definition
Forces that hold molecules of the same type together
Adhesion
definition
Forces that hold molecules of different types together
Surface tension
definition, relationship to IMFs
Property of a liquid surface that allows it to resist external force
Stronger IMFs = more surface tension
Vaporization
liquid to gas
Condensation
gas to liquid
Melting
solid to liquid
freezing
liquid to solid
sublimation
solid to gas
deposition
gas to solid
vapor pressure
definition, relationship to IMFs
in a closed container, the pressure of the gas phase substance once vaporization and condensation have achieved equilibrium
stronger IMFs = lower vapor pressure
boiling point
definition, relationship to IMFs
the point at which vapor pressure is equal to external atmospheric pressure
stronger IMFs = higher boiling point
how is boiling point related to pressure?
if atmospheric pressure is low (i.e. higher altitude), the boiling point will be lower
what is a state function
something is a state function when the energy is determined by the starting and ending point, not by the path taken
triple point
define and identify
on a phase diagram, this is the point where all phases of a substance can exist simultaneously
critical point
define and identify
on a phase diagram, this is the point past which it becomes difficult to tell a liquid from a gas
