thermodynamic scale of temp.
The thermodynamics scale of temperature does not depend on the property of any particular
substance and has an absolute zero.
what is the absolute zero
The absolute zero is the temperature at which all substances have a minimum internal energy.
* Internal energy will be discussed in greater detail in topic on thermodynamic systems
what is an ideal gas
An ideal gas is a gas that obeys the equation pV = nRT (or pV =NkT) at all pressure p, volume V
and temperature T.
what is meant by the mole
One mole is the amount of substance that contains 6.02 × 1023 particles.
state the basic assumptions of the kinetic theory of gases
- A gas consists of a large number of molecules.
- The molecules are constantly in random motion. (Newtonian mechanics can apply)
- The molecules collide elastically with the container and with each other.
- The duration of collision is negligible compared to the time interval between collisions.
- There are no intermolecular forces except during collisions.
- The total volume of molecules is negligible compared to the volume of the container.
How does random motion of gas particles exert mechanical pressure on the wall?
A gas consists of a large number of molecules which are constantly in random motion.
The molecules collide with the wall of the container and bounce off.
The direction of (velocity and) momentum of the molecules changes during the collision with the wall, so there is a change in momentum of the molecules during the collision and by Newton’s second law,
force is exerted on the molecules by the wall.
By Newton’s third law, the molecules exert force on the wall and exerts mechanical pressure on the wall.
what is meant by the internal energy of the system
The internal energy of a system is the sum of a random distribution of microscopic kinetic and potential energies associated with the particles (or molecules) of the system.
what is the relationship between thermodynamic temperature of a system and mean/average microscopic kinetic energy of particles
The thermodynamic temperature of a system is directly proportional to the average microscopic kinetic energy of the particles in a system.
how does the phase of the system affect the microscopic energy of the particles
phase of system affect the intermolecular forces between the molecules. the larger the intermolecular forces of attraction, and the smaller the separation between molecules, there is smaller microscopic potential energy of the particles
thermal equilibrium
Two bodies are in thermal equilibrium if there is no net flow of heat between them when they are in
thermal contact.
what happens when 2 systems are placed in thermal contact
energy is
transferred (by heating) from the system at higher temperature to the system at lower
temperature, until they reach the same temperature and achieve thermal equilibrium
what is the 0th law of thermodynamics
If two systems are each in thermal equilibrium with a third system, then they are also in thermal
equilibrium with each other.
what is the first law of thermodynamics
The first law of thermodynamics states that the increase in internal energy of a system is equal to the sum of the heat supplied to the system and the work done on the system.
specific heat capacity
The specific heat capacity of a substance is the heat required per unit mass per unit temperature
change to raise the temperature of the substance without a change in phase of the substance.
formula for internal energy of monoatomic gas
U = 3/2 pV
specific latent heat
The specific latent heat of a substance is the heat required per unit mass to change the phase of
the substance without a change in temperature.
specific latent heat of fusion
The specific latent heat of fusion of a substance is the heat required per unit mass to change the
phase of the substance between solid and liquid phase without a change in temperature.
