4. Thermodynamics Flashcards
(41 cards)
what do open systems exchange
both mass and heat/energy with their surroundings
what do closed systems exchange
heat and energy but not mass
what do isolated systems exchange
not heat/energy or mass
internal energy is the average total of what
average total mechanical energy (kinetic + potential) of the particles that make up the system
what is conduction
what does it require
thermal energy transfer via molecular collisions
requires direct physical contact and process involves higher energy molecules of one system transferring some of their energy to lower energy molecules of the other system via molecular collisions
what is convection
thermal energy transfer via fluid movements
why do warm fluids move in direction of cooler fluid
due to differences in pressure or density
what is radiation
thermal energy transfer via electromagnetic waves
what is the first law
energy of system and its surroundings is always conserved
what is the equation for the first law
change in internal energy = quantity of heat supplied to system by surroundings + net work done by system
U = Q + W
what is + W
work done on system
what is -W
work done by system
what is +Q
heat added to system
what is -Q
heat given off by system
what is the second law
heat cannot by completely changed to work in a cycle-like process
what is the symbol and SI unit for internal energy
U - joule
what is the symbol and SI unit for temperature
T = kelvin
what is the symbol and SI unit for pressure
P = pascal
what is the symbol and SI unit for volume
V = m^3
what is the symbol and SI unit for enthalpy
H = kJmol^-1
what is the symbol and SI unit for entropy
S = JK^-1mol^-1
what is the symbol and SI unit for gibbs energy
G = kJmol^-1
for a reaction in a system with constant volume is work done
no work of any kind is done and the change in internal energy is equal to the heat
for a fluid temperature is directly proportional to what
translational kinetic energy of molecules
