# CHMB20 Chapter 1

162 views4 pages
Published on 27 Sep 2011
School
UTSC
Department
Chemistry
Course
CHMB20H3
Chapter 1: The Properties of Gases
The Perfect Gas
Gas: a form of matter that fills any container it occupies.
oIt is in continuous random motion.
oAverage speeds increase as the temperature is raised.
oExcept during collisions, the molecules of a gas are widely separated
from one another and move in paths that are largely unaffected by
intermolecular forces.
Equation of State: p= f(T, V, n)
Equation of State of a Perfect Gas: p= nRT/V
oPressure (p)= F/A to which theforce is applied F= mg, m= ρV,
where ρ is mass density.
The greater force acting on a given area, the greater the
pressure.
If two gases are in separate containers that share a common
movable wall, the gas that has the higher pressure will tend to
compress the gas that has lower pressure.
Mechanical Equilibrium: when the two pressures are equal and
the wall has no tendency to move (high pressure lowers and low
pressure increases).
Barometer: measures the pressure exerted by the atmosphere.
Hydrostatic Pressure (p)= ρgh, where g is gravity and h is the
height.
Bayard-Alpert Pressure Gauge: interpretation of pressure is
based on the ionization of molecules present in the gas and the
resulting current of ions.
Capacitance Manometer: the deflection of a diaphragm relative
to a fixed electrode is monitored through its effect on the
capacitance of arrangement.
oTemperature (T): the property that indicates the direction of the flow of
energy through a thermally conducting, rigid wall.
When energy flows from A to B when they are in contact, then
we say that A has a higher temperature than B (high temp will
flow towards low temp).
Diathermic Boundary: if a change of state is observed when two
objects at different temperatures are brought into contact
(metal container).
Adiabatic Boundary: if no change occurs even though the two
objects have different temperatures (vacuum flask).
Thermal Equilibrium: established if no change of state occurs
when two objects A to B are in contact through a diathermic
boundary.
Zeroth Law of Thermodynamics: if A is in thermal equilibrium
with B, and B is in thermal equilibrium with C, then C is also in
equilibrium with A.
Perfect-Gas Temperature Scale/ Thermodynamic Temperature
Scale: using the pressure of a gas and is independent of the
identity of the gas.
T/K= θ/°C + 273.15, where θ is the temperature of the Celsius
scale (implies that a difference in temperature of 1°C is
equivalent to a difference of 1K 25°C = 298.15K).
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