CHEM 1300 Lecture Notes - Lecture 17: Molecular Mass, Pressure Cooking, Polarizability
26 Jun 2018
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Lecture 17 – Intermolecular/Intramolecular Forces and Solids
●Phases in general have definite properties:
oFairly unique to each structure
oState (solid, liquid, gas) can have multiple phases
▪Snow, ice, hail
▪Called Polymorphism
oTransitionary state changes:
▪Melting/freezing
▪Vaporization/condensation
▪Deposition/sublimation
oStates: solid, liquid, gas
▪Phases contained within states
●Solid States:
oProperties:
▪Does not flow freely (electrons, atoms, molecules)
▪Difficult to compress
▪Distinct and definite volume
●Only air can be forced out
▪Atoms interacting very strongly
●Polymorphism is usually present in this situation
oDue to different ways the compounds can form into isomers
●Liquid States:
oProperties:
▪Particles have more space to flow around the container
▪Definite volume
▪Difficult to compress
▪Slightly weaker intermolecular forces than solid state but still has attraction
(cohesion)
●Gaseous States:
oProperties:
▪Particles flow very freely
▪Can be compressed easily/condensed into a liquid state
▪To know gas volume, we need temperature and pressure information
▪Very few atomic interactions
●Phases:
oVaporization:
▪Evaporation
▪Temperature increases from adding extra energy into the system
▪NRG overcomes intermolecular forces
▪SA increases
▪Increase number of collisions to increase rate of vaporization (increase in
transfer of energy between atoms)
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Document Summary
Solid states: properties, does not flow freely (electrons, atoms, molecules, difficult to compress, distinct and definite volume. Only air can be forced out: atoms interacting very strongly. Polymorphism is usually present in this situation: due to different ways the compounds can form into isomers. Liquid states: properties, particles have more space to flow around the container, definite volume, difficult to compress, slightly weaker intermolecular forces than solid state but still has attraction (cohesion) Gaseous states: properties, particles flow very freely, can be compressed easily/condensed into a liquid state, to know gas volume, we need temperature and pressure information, very few atomic interactions. Heating of a liquid in an open system. Temp of a liquid remains constant after boiling. Additional nrg towards breaking bonds and releasing gas. When vapour pressure = barometric pressure, liquid will always boil. When adhesion is greater than cohesion: meniscus is lower. When cohesion is greater than adhesion: meniscus is higher: capillary action:
