Chapter 2 + 3 - Work, Energy & Thermodynamics Flashcards
Conservative forces:
path independent and do not dissipate the mechanical energy of a system
ex: gravity + electrostatic forces
Nonconservative forces:
path dependent and cause dissipation of mechanical energy from a system
ex: friction, air resistance, viscous drag
Work:
energy is transferred from one system to another
Work-Energy Theorem:
when net work is done on or by a system, the system’s kinetic energy will change by the same amount
in more general applications - the work done on or by a system can be transferred to other forms of energy as well
Zeroth Law of Thermodynamics:
objects are in thermal equilibrium when they are at the same temperature
Isolated Systems
Closed Systems
Open Systems
Isolated: do not exchange matter or energy with the surroundings
Closed: exchange energy but not matter with their surroundings
Open: exchange both energy and matter with their surroundings
First Law of Thermodynamics:
the total energy in the universe can never decrease or increase
Specific heat of water:
1 cal/(g * K)
When work is done BY a system
vs.
When work is done ON a system
(consider gases)
When work is done by a system (the gas expands), the work is said to be positive
When work is done on a system (the gas compresses), the work is said to be negative
Terms for Phase Change:
solid to liquid
fusion or melting
calorie (c) vs. Calorie (C)
One calorie (little c) is the amount of heat required to raise 1 g of water one degree Celsius
One Calorie (big C) is the amount of heat required to raise 1 kg of water 1 degree Celcius, equl to 1000 calories
Terms for Phase Change:
Liquid to solid
freezing or solidification
Terms for Phase Change:
Liquid to gas
boiling, evaporation or vaporization
Terms for Phase Change:
Gas to Liquid
condensation
Terms for Phase Change:
solid to gas
sublimation
Terms for Phase Change:
gas to solid
deposition
Thermal Equilibrium:
if no net heat flows between two objects in thermal contact
State Functions:
thermodynamic properties that are a function of only the current equilibrium state of a system
defined by the fact that they are independent of the path taken to get to a particular equilibrium state
pressure, density, temperature, volume, enthalpy, internal energy, gibbs free energy, entropy
Process Functions:
describe the path taken to get to from one state to another
work and heat
Isothermal:
constant temperature, and therefore no change in energy
ΔU = 0
ΔU = Q - W → Q = W
Adiabatic:
no heat exchange
Q = 0
ΔU = Q - W → ΔU = -W
Isovolumetric + Isochoric:
no change in volume; therefore no work accomplished
W = 0
ΔU = Q - W → ΔU = Q
Isobaric:
processes that occur at constant pressure
