Characteristics and strength of:
london dispersion
weak
occurs between all molecules; strenght depends on size, polarizability
Characteristics and strength of:
hydrogen bond
moderate
occurs between molecules with O-H, N-H, and F-H
Why don't the boiling points of NH3, H2O, and HF not follow the trend of increasing boiling points with increasing molecular mass down a gorup of hte periodic table
due to Hydrogen bonds the boiling point has to be higher to break the bonds
What us surface tension and why does it occur?
resistance of a liquid to spread out and increase its surface area
due to tighter attraction at the surface
Viscosity
Relationship with temperature
measure of a liquid's resistance to flow
Increase temperature, decrease viscosity
What's one common way of getting from ne phase to another?
temperature change: breaking weak interactiosn; adding kinetic energy to additional molecules
What is enthalpy?
Temp adn entropy relationship
heat content of materials
increase temp, increase entropy
Solid to a liquid
fusion (melting)
What does frost resemble?
a crystalline appearance
Phase changes
a change in physical form but not the chemical identity of a substance
liquid to gas
vaporization
gas to liquid
condensation
liquid to solid
freezing
solid to gas
sublimation
Molar Heat of Fusion
energy required to melt one mole of a solid in kJ
Molar Heat of Vaporization
the energy required to vaporize one mole of liquid