Thermodynamics Flashcards
Define mechanical work
It is defined as the product of force and distance in the direction of the force-> the rate of work transfer measured in watts
Define heat
transitory energy exchanged due to a difference in temperature between a system and its surroundings
Define a system
a region in space containing matter under consideration within some closed surface called the boundary of the system
Define a boundary
it separates a system from the surroundings; heat and work can cross the boundary
Define surroundings
they are outside the system but close enough to be affected by changes within the system
Define a universe
a system and its surroundings form a universe
Define an isolated system
a system that cannot exchange either energy or matter outside the boundaries of the system
Define an open system
matter can cross the boundary
Define a closed system
matter cannot cross the system
Define a property
it describes the conditions of the system in a specific state
Define intensive properties
properties that are independent of the mass of the system
e.g. temperature and pressure
Define extensive properties
properties that are proportional to the mass of the system
e.g. total volume and total energy
Define a specific property
a property that is per unit mass of matter in the system
Define a state
condition of a system as defined by the relevant properties
Define internal energy
It is defined as the total energy of a closed system. It is a sum of the potential and kinetic energies of the system
Define equilibrium
a system is in thermodynamic equilibrium when no changes of state are taking place
Define a process
the transition of a system from one state to another
Define a cycle
a closed system passes through a series of states in such a wat that the final state is equal to the initial state
What are the three assumptions made when using the Kinetic Theory of Gases to model the behaviour of Perfect Gasses?
The particles are perfectly rigid, therefore all collisions are perfectly elastic
The total volume occupied by the particles is negligible when compared to the total volume occupied by the gas
There are no attractive and repulsive forces between the particles
Define the unified atomic mass
u = (Mass of C-12 atom)/12
What is Avogadro’s Law?
Equal volumes of all gases contain the same number of particles when at the same temperature and pressure
What is Dalton’s Law?
The pressure of a mixture of gases is equal to the sum of the partial pressures of the constituents
Define the specific heat of a substance
It is defined as the quantity of heat required to cause unit temperature rise in unit mass
