3 Main Forces
Additional Forces
Vaporization
Phase Changes
Phase Diagram
100
When is dipole-dipole attraction most notable? (what state of matter)
Liquid
100
What state of matter does viscosity deal with?
liquid
100
Define boiling point
The temperature where vapor pressure equals atmospheric pressure
100
What is it called when you go from a solid to a liquid? (endothermic or exothermic)
Melting endothermic
100
Define triple point
The conditions under which a substance has all three states of matter in equilibrium with one another.
200
When bonded with which elements is hydrogen the strongest?
F, O, N
200
Describe viscosity and what happens when it is high or low?
Viscosity is the resistance of a liquid to flow
200
Define vapor pressure
Pressure exerted by a liquid’s vapor in equilibrium with its liquid phase
200
What do you call it when you go from liquid to gas? (endothermic or exothermic)
Vaporization endothermic
200
Define critical point
The temperature and pressure above which a substance cannot exist as a liquid.
300
What are the 3 main forces? Define them.
dispersion forces: weak temporary attraction
Dipole-Dipole: a positive and negative attract (polar molecules)
Hydrogen bond: a dipole dipole reaction involving hydrogen molecule
300
Give 3 examples of viscous liquids.
Honey, Motor Oil, Syrup, Glycerol
300
Describe the relationship between boiling point and vapor pressure
High Vapor Pressure > Low Boiling Point
Low Vapor Pressure > High Boiling Point
300
What do you call it when you go from gas to liquid (endothermic or exothermic)
condensation exothermic
300
What happens to something after it passes the critical point
A substance becomes a supercritical fluid after this point
400
What happens to the boiling point during dipole-dipole (higher or lower), why?
They raise the boiling point because more energy is needed to separate the molecules
400
_______ ______ give rise to _______ ______
_____ exhibits high _____ ______ due to very strong _______ ________
Cohesive forces, surface tension
Water, surface tension, hydrogen bonding
400
Which liquid has the strongest intermolecular forces? Why?
Ethanol (due to hydrogen bonding)
400
What do you call it when you go from gas to solid (endothermic or exothermic)
Deposition endothermic
400
Label the Diagram
A = Solid
B = Liquid
C = Gas
500
What do dispersion forces depend on (define the term)
Polarizability: How easily a molecule’s electron cloud becomes temporarily distorted, allowing it to attract nearby molecules through weak forces
500
If adhesive forces > cohesive forces,
If adhesive forces < cohesive forces,
the substance spreads out on the surface (like water on glass)
the substance does not spread out (like water beading up on wax)
500
Which liquid has the lower boiling point? Why?
Dimethyl Ether (due to weak intermolecular forces)
500
What do you call it when you go from solid to gas (endothermic or exothermic)
sublimation exothermic
500
What phase would the compound be at the following temperatures and pressures?
25 C & 1.8 atm?
75 C & 1.2 atm?
95 C & 1 atm?
Solid, Liquid, Gas