Thermal physics & Ideal gases Flashcards
Definition
Internal energy
Sum of random kinetic and potential energies of the atoms in a system
Definition
First law of thermodynamics
Increase internal energy = thermal energy transferred + work done on a body
Formula
Work done equals
Pressure * Change in volume
Definiton
Isothermal change
Change of a system where the temp remains constant
Definition
Specific heat capacity
Energy required by unit mass per unit temperature change
Formula
Specific heat capacity equals
E / (Mass * Change in Temp)
Definition
Specific latent heat of fusion
Amount of heat energy per unit mass needed to convert solid to liquid without change in temp
Definition
Specific latent heat of vaporization
Amount of heat energy per unit mass needed to convert liquid to gas without change in temp
Formula
Specific latent heat equals
Energy / Mass
Definition
Heat energy (Thermal energy)
Energy transferred from one object to another because of a temp change
Definition
Absolute zero
Temperature where a system has minimum internal energy (0K or -273C)
Definition
Boyle’s law
The pressured exerted by a fixed mass of gas is inversely proportional to its volume, if temp is constant
Definition
Charles’s law
Volume occupied by a gas at constant temp is directly proportional to its thermodynamic temp
Definition
Ideal gas
Gas that behaves according to the equation pV = NRT
Formula
2 Ideal gas equations
pV = nRT
pV = NkT
Definition
Kinetic theory of gases (Volume)
Volume of particle is neglegible compared to volume of gas (as liquid boils to become gas, particles become further apart)
Definition
Kinetic theory of gases (Force)
Force between particles are negligible, except during collision (if attracted strongly, they would end up in the middle of the container)
Definition
Kinetic theory of gases (Time of collision)
Time of collision with walls is negligible compared with the time between collisions (molecules considered as hard spheres)
Definition
Kinetic theory of gases (number of particles)
Large number of particles moving random that collide elastically with walls and with each other (Internal energy of gas is the total kinetic energy of the particles)
Formula
Pressure of an ideal gas equals
p = 1/3 * (Number of molecules * Mass / Volume) * mean_square speed
Formula
Kinetic energy of a molecule equals
3/2 * k * Temp
Definition
Root mean square speed
The square root of the average of the squares of the speeds of all the molecules in a gas
