CHM 141 final Flashcards
conversion from one state of matter to another
Phase change
the change in enthalpy to melt a solid into a liquid
heat of fusion
the change in enthalpy to turn a liquid into a gas
heat of vaporization
the change in enthalpy to change a solid to a gas without passing through the liquid phase
heat of sublimation
vaporization + fusion =
sublimation
what equation should you use for the line B-C on a heating curve? (flat line)
q =m*heat of vaporization/ heat of fusion
what equation should you use for the line E-F on a heating curve? (increasing line)
q = mCs delta T
The temperature beyond which a gas cannot be compressed/ the highest temperature a liquid can exist as a liquid
Critical Temperature
Critical temperature—–with increasing intermolecular forces
increases
the pressure required to liquify a substance at critical T
Critical Pressure
occurs when critical T and P are surpassed and liquid and gas phases are indistinguishable from each other
Supercritical fluid
the pressure exerted by a vapor on the surface of a liquid during dynamic equilibrium,
Vapor Pressure
when two opposing processes are occurring simultaneously
dynamic equilibrium
True or false the relationship between vapor pressure and temperature is linear?
False, they do generally increase as the other increases but it is not linear
liquids that easily evaporate with high vapor pressures and low intermolecular forces
Volatile liquids
When the vapor pressure of a substance = the external pressures acting on the surface of the liquid where thermal E is enough to break intermolecular forces and create a gas
Boiling point
does boiling point increase or decrease at higher pressures?
Increases at higher pressures
the boiling point of a substance at 1 atm
normal boiling point
where all states of matter exist in equilibrium
triple point
solids with a ‘sea’ of delocalized valence electrons that conduct heat and electricity well
metallic solids
solids held together by cation and anion attractions, don’t conduct electricity well and are brittle
ionic solids
solids held together by a network of covalent bonds
covalent-network solids
individual molecules held together by weak intermolecular forces, soft with low melting points
molecular solids
chains of carbon bonded to adjacent chains held together by intermolecular forces, more flexible than other solids
polymers