First Law Of Thermodynamics Flashcards
- Is constantly happening around
us. - Energy always originates from a source.
- Energy cannot be created or destroyed; it can only
change form. - Law of conservation of energy
- First law of thermodynamics
*One of the most fundamental laws in the universe
Energy Transmission
*Specific part of the universe understudy
*Can be as small as an atom or as big as a planet
System
*Everything else outside the system is called the
Surroundings
(matter and energy can pass through
its boundaries)
ex. Human body, Planets, Plants
Open System
(only energy can pass through its
boundaries)
ex. Light bulb, Pan with lid
Closed System
(matter and energy CANNOT pass
through its boundaries)
ex. Thermos flask
Isolated System
*Sum of all the kinetic and potential energies of
the components of the system.
*Not only the motions and interactions between
the molecules but also the interaction of their
nuclei and electrons.
*Absolute value is difficult to measure
*We are more interested in the changes
Interal energy
Thermodynamic quantities have three parts
*A number
*A unit
*A sign
*It determines the magnitude of the
quantity
Unit
*It determined the direction of the quantity
* any increase in the energy of the system is
accompanied by a decrease in the energy of the
surroundings
Sign
is defined as the transfer of thermal
energy between two systems due to a
temperature difference. It is a form of energy in
transit.
is essentially the energy associated with
random motion of atoms and molecules
Heat
- energy transferred to or from a system by a
macroscopic force acting through a distance.
*Ordered molecular motion
Work
____ – random molecular motion, transfer due to
temperature difference
Heat
_____ ordered molecular motion, same direction,
transferred by achieving motion against an opposing
force
Work
___________ – process in which energy is
acquired from its surroundings as heat
Endothermic
