First Law of Thermodynamics Flashcards
states that energy cannot be created or destroyed but can only be transformed or changed from one form to another
First Law
exists in numerous forms such as thermal, mechanical, electric, chemical and nuclear
energy
can be considered a form of energy
mass
Two distinct forms energy can be transferred
heat, work
For a controlled volume, energy can also be transferred by _______.
mass flow
Without it, there can be no work or heat flow that can happen.
energy
unit of energy in SI system and English system
Joules, BTU
amount of energy required to apply a force of 1 Newton over a distance of 1 meter
1 Joule
amount of energy required to increase the temperature of 1 pound water by 1 degree Fahrenheit
BTU
Energy that a system possesses as a result of its elevation in a gravitation field; in simple terms, the energy due to height of a system
potential energy
Energy that a system possesses as a result of its motion relative to some reference frame
kinetic energy
energy stored in a system in a microscopic scale
internal energy
Multiplying it by the mass gives us the internal energy U
specific internal energy u
defined as the form of energy that is transferred between two systems (or a system and its surroundings) by virtue of a temperature difference
heat
A process where there is no heat transfer
adiabatic process
Two Ways a Process is Adiabatic
- system is well insulated
- both system and surrounding are at same temperature
When heat is added to the body or system, Q is _____.
positive
When heat is rejected by the body or system, Q is _____.
negative
energy interaction between a system and its surroundings
work
energy transfer associated with a force acting through a distance
work
If work is done by the system, it is _____.
positive
If work is done on the system, it is _____.
negative
Work of a non-flow system occurs in a _______ system
closed
work done in pushing a fluid across a boundary, usually into or out of a system
flow work or flow energy
Work of a flow system occurs in an _______ system
open
used to combine the change in internal energy with this flow work, to make calculations more convenient
enthalpy
defined as a region in space that is under consideration; contains mass or a thermodynamic substance
thermodynamic system or control volume
has specific boundaries that separate it from the external effects of the environment
thermodynamic system or control volume
Systems where energy (heat and work) and mass cross the system
boundary
Open Systems (Steady Flow Systems)
Systems where energy (heat and work) can cross the system boundary but not mass
Closed Systems (Non-Flow Systems)
Systems where both energy (heat and work) and mass cannot cross
the system boundaries; totally isolated by the environment
Isolated Systems
