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Reference Guide

Thermodynamics - Reference Guides

4 pages1388 viewsFall 2015

Department
Chemistry
Course Code
CHEM 11100
Professor
All
Chapter
Permachart

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Thermodynamics
THERMODYNAMICS BASICS
Adiabat: Line or path describing adiabatic process
Adiabatic process: Heat is not transferred into or out of system
Boiling point: Temperature at which liquid under fixed pressure
converts to vapor
Carnot cycle: System undergoing cyclical process with 4 reversible
changes
Carnot engine: Most efficient heat engine which carries out the
Carnot cycle
Critical point: Temperature and pressure at which liquid and vapor
become identical
Cyclical process: Repeats sequence of changes in system
Enthalpy (H): Quantity of heat in substance/unit mass under
constant pressure
Entropy (S): Thermodynamic property related to degree of disorder
in a system
Heat (qor Q): Form of energy transfer resulting from temperature
difference
Heat capacity (C): Total amount of heat to produce a 1 degree rise
in temperature of a given substance
Heat engine: Converts heat into mechanical energy
Internal energy: Total kinetic and potential energy at the molecular
level
Isobaric process: Process involving constant pressure in the system
Isochoric process: Process involving constant volume
Isotherm: Line describing an isothermal process
Isothermal process: Process involving constant temperature
Latent heat of fusion (Lf): Amount of heat needed to convert unit
mass of solid to liquid at same temperature
Latent heat of vaporization (Lv): Amount of heat needed to
convert unit mass of liquid to vapor (same temperature)
Liquefaction point: Temperature at which vapor or solid converts to
a liquid
Melting point: Temperature at which solid sub stance melts at a
fixed pressure
Pressure (por P): Force acting on a unit area
Saturated liquid: State of liquid in which vapor begins to form
Saturated vapor: State of vapor in which liquid is vaporized
Specific volume (
u
): Vol. per unit mass of a substance
Subcooled (compressed) liquid: Liquid at temperature which
permits transition to another more stable phase without
transformation into an even more stable phase
Sublimation: Phase transition of a substance from solid to vapor
phase
Supercritical state: Pressure and temperature are greater than at
critical values
Superheated liquid: Liquid is at temperature higher than its boiling
point without conversion to gaseous state
Superheated vapor: Vapor at temperature higher than boiling point
at given pressure
Thermodynamics: Study of storage, transfer, and transformation of
energy
Triple point: Temp erature and pressure at which solid, liquid, and
vapor co-exist
Vaporization: Passage of mol ecules from a liquid to a gaseous phase
Work (wor W): Form of energy transfer that can be expressed as a
force acting through a distance
DEFINITIONS
CONVERSION FACTORS
Energy
1J= 1 kg-m2/s2
= 0.239 cal = 1 N-m
= 2.78 ¥10–7 kWh
1 cal = 4.184 J
1eV= 1.602189 ¥10 –19 J
1 eV/atom = 96.485 kJ/mol
1 kWh = 3600 kJ
1 Btu = 778 ft-lbf
= 252 cal
= 1060 J
Volume
1L= 1000 mL
= 1000 cm3
= 61.0 in3
= 1.056688 qt
1 qt = 2 pt = 32 fl oz
1 gal = 3.785412 L
= 128 fl oz
1 ft3= 28.3 L
= 1728 in3
Temperature
TF= (9/5 ¥TC) + 32
TC = 5/9(TF– 32)
TR= TF+ 459.67
TK= TC+ 273.15
Force
1 N = 1 kg-m/s2
= 0.225 lbf= 105D
1 lbf= 4.45 N
= 32.17 lbm-ft/s2
Mass
1 slug = 32.2 lb = 14.6 kg
1 kg = 1000 g
= 2.2046226 lb
1 lb = 453.59237 g = 16 oz
Length
1 m = 3.28 ft = 39.37008 in
1 mi = 1.61 km = 5280 ft
1 in = 2.54 cm
Pressure
1 atm = 1.01 ¥105N/m2
= 101325 Pa
= 760 mm Hg
= 760 Torr
= 14.6959 psi
= 29.9 in Hg
= 1.01325 bar
WORK & H E AT
Work and heat are quantities that result from energy transfer;
work is associated with expansion or compression of gases
• Plotting Pvs. Vis a simple way to calculate work done on a
system
• Work is area under curve
• Each point on Pvs. Vgraph has an equation of state
• Graph shows a piston moving in a compressed gas system
• As gas expands (contracts), pressure and volume change;
hence, equation of state will be different
• Work done on system depends on initial state (i), final
state (f), and intermediate states
• Total work done on system is W = PDV, where P
is pressure of surround ings, Vis volume, and Wis
work
• By con vention, DV is expressed as final minus
initial volumes (that is, DV = Vf– Vi)
Example:
Find work done along path bto con Pvs. V
graph
Solution: Wbc = P(Vc– Vb)= (6 ¥105Pa) ¥
(0.05 m30.02 m3) = 1.80 ¥104 J, where Wbc
is work along path bc, Pis pressure, and Vband
Vc are volumes at points band c, respectively
P
W = PV
V
WP = W
V
V = W
P
P
V
0.02
d
5x105
2x105
0.05
a
c
b
PV Work
Thermodynamics
l e a r n r e f e r e n c e r e v i e w
TM
permacharts
THERMODYNAMICS • 1-55080-860-51© 1999-2013 Mindsource Technologies Inc.
w w w . p e r m a c h a r t s . c o m
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