Thermodynamics
THERMODYNAMIC PROPERTIES
THERMODYNAMIC PROPERTIES
Thermodynamic properties describe measurable characteristics of a substance.
A knowledge of these properties is essential to the understanding of
thermodynamics.
EO 1.1
DEFINE the following properties:
a.
Specific volume
b.
Density
c.
Specific gravity
d.
Humidity
EO 1.2
DESCRIBE the following classifications of
thermodynamic properties:
a.
Intensive properties
b.
Extensive properties
Mass and Weight
The mass (m) of a body is the measure of the amount of material present in that body. The
weight (wt) of a body is the force exerted by that body when its mass is accelerated in a
gravitational field. Mass and weight are related as shown in Equation 1-1.
wt =
(1-1)
mg
gc
where:
wt
=
weight (lbf)
m
=
mass (lbm)
g
=
acceleration of gravity = 32.17 ft/sec2
gc
=
gravitational constant = 32.17 lbm-ft/lbf-sec2
Note that gc has the same numerical value as the acceleration of gravity at sea level, but is not
the acceleration of gravity. Rather, it is a dimensional constant employed to facilitate the use of
Newton’s Second Law of Motion with the English system of units.
The weight of a body is a force produced when the mass of the body is accelerated by a
gravitational acceleration. The mass of a certain body will remain constant even if the
gravitational acceleration acting upon that body changes.
Rev. 0
Page 1
HT-01
