KTG and Thermodynamics Flashcards
Internal Energy definition based on kinetic theory of gases
I.E. = Kinetic Energy of the gas as the intermolecular forces between the gaseous molecules is assumed to be zero, hence zero potential energy
Brownian Motion
Random motion of the gaseous molecule
Force imparted by one molecule on the container
mv^2/3L
What is the value of Vrms, Vavg, Vmp?
Vrms =root(3RT/Mo)
Vavg = √8RT/πMo
Vmp = root(2RT/Mo)
The average velocity of gases is 0.
What is the ideal gas equation?
PV=nRT
P = Pressure of the gas
V = volume of the gas
n = no. of moles
R = Universal Gas constant
T = Temperature
Boyle’s Law
Temperature is constant
P is inversely proportional to volume
Charle’s Law
Pressure is constant
Volume is directly proportional to temperature
Gay Lussac’s Law
Volume is constant.
Pressure is directly proportional to temperature
Avagadro’s Number
At same temperature, pressure and volumes, gases will contain equal number of molecules.
N1 = N2
Dalton’s Law of Partial Pressure
Total pressure exerted by a mixture of non-reactive gases is equal to sum of individual pressure exerted by each gas
Graham’s law of diffusion
Rate of diffusion of gases are inversely proportional to square root of of the density of the gas
Mean Free Path
It is the average distance travelled by a gaseous molecule between any two successive collision.
Degree of Freedom
Total number of independent term in the kinetic energy of the gaseous moelcule
DOF of monoatomic gaseous molecule and its internal energy
3(Translational Kinetic Energy)
Total internal energy = 3nrt/2
DOF of diatomic gaseous molecule and its internal energy
DOF = 5(3 translational and 2 rotational)
U = 5nRT/2
U = 7nRT/2(For very high temperature, a vibrational KE is also added)
DOF of polyatomic gaseous molecule (Linear) and and its internal energy
DOF = 5(3 translational and 2 rotational)
U = 5nRT/2
DOF of polyatomic gaseous molecule (Non-Linear) and and its internal energy
DOF = 6(3 translational and 3 rotational)
U = 3nRT
Mayer’s Formula
Cp=Cv+R
Value of change in internal energy
nCv△T
Types of thermodynamic system
Open System - Both energy and matter can be exchanged between system and surrounding
Closed System - Only energy exchange is possible
Isolated System - Neither energy nor matter can be exchanged between system and surroundings
Work done by an ideal gas
dW = PdV
Work done is the area under the PV curve
Zeroth Law of Thermodynamics
If A and B are in thermal equilibrium, and B and C are in thermal equilibrium, then A and B are in thermal equilbrium.
First Law of Thermodynamic
Q = △u + Workdone
What is the specific heat capacity?
Q=mS△T
m =mass of the substance
△T = Change in temperature
Molar Heat Capacity
Q = nC△T
n = no. of moles
Internal Energy is a function of
△T
It only depends upon the initial and final point, and not on the path followed. Hence is a state function
Molar Heat Capacity at constant volume and pressure
Constant Volume: Q = nCv△T
Constant Pressure: Q = nCp△T
Work done by Isobaric, Isochoric, Adibatic and Isothermal
W = nr△T, 0, nRTlnv2/v1 or nRTlnP1/P2, -nR△T/y-1
Conditions for adibatic process
PV^y = Constant
TV^y-1 = Constant
P^1-yT^y = Constant
Work done by polytropic process(PV^x = constant)
Work done = nR(T1-T2)/x-1
Free Expansion of a gas
Expansion of gas by doing no work done, and the moles are accordingly distributive
Cvmix
n1Cv1+n2Cv2/(n1+n2)
Cpmix
n1Cp1+n2Cp2/(n1+n2)
ymix is
Cpmix/Cvmix
Latent Heat
Amount of heat required to change the state or phase of a substance at their melting point and boiling point without the change in temperature
Latent Heat of Fusion
Heat required to change 1unit of ice at 0 degree to 1 unit of water at 0 degree without any change in temperature
Latent Heat of Vaporisation
Heat required to change 1unit of water at 100 degree to 1 unit of water vapour at 100 degree without any change in temperature
Efficiency of cyclic process
Total work done/ Heat absorbed
Efficiency of the heat engine
Total Work/Heat Absorbed
1-Q2/Q1, where Q2 is the heat gain without change in temperature and Q1 is the heat giving change in temperature
Clausius Statement
It is impossible for self acting engine to transfer the heat from colder body to hotter body without external aid.
Kelvin-Planck Statement
It is impossible to design an engine that extracts heat and fully utilised it into work without producing any other effect.
Coefficient of Performance
Heat Absorbed/Work done
