CHEM 120 Lecture Notes - Lecture 1: Kinetic Theory Of Gases, Ideal Gas, Stoichiometry
CHEM 120 – Lecture 1 – General Overview/Gases
What is Chemistry?
The study of matter and its properties , its changes and the energy associated with them
Matter: things you can see, smell, taste and touch; anything with mass and volume
Central theme of chemistry?
Macroscopic properties and behaviour of substances that we can see or easily measure
result from atomic scale properties and behaviours
oUnderstand and apply ideal gas laws
oFor gases, ow are physical variables of pressure, volume, temperature and
number of moles related?
oProperties of mixtures of gases
oGases in chemical reactions; relationship between reaction stoichiometry and
oStudy the kinetic molecular theory of gases
oNon-ideal (real) gases
What is a gas?
oFills and assumes the shape of its container
oDiffuses and mixes in all proportions with other gases
There are four variables/parameters that describe any gas
oNumber of moles proportional to mass
oForce per unit area
oEvangelista Torricelli: discovers atmospheric pressure
oMercury falls to 76 cm when inverted
oHg levels changes until pressure from Hg column = atmospheric pressure
oDoes not depend on diameter of tube
oVolume = Area x height
oMass = Volume x density = Area x height x density
oForce = mg = Ahdg
The pressure exerted by a liquid depends on:
oHeight of column of liquid
oDensity of column of liquid
oDetermines the pressure of confined gases