Ramesh V
Last Activity: 15 Years ago
Any Change in the Internal Energy of a System U is due to either the Heat Flow into/out-of the System or due to Work Done by/on the System provided the system's center-of-mass energy does not change,
the first law as ΔU=Q+W
HEAT Q:
Energy Transfer across the System's Boundaries that cannot produce Macroscopic-Mechanical Motion of the system's Center-of-Mass. Energy Transfer at the Molecular Level .
Q = Microscopic Energy flow into (or out of) the System
ENERGY FLOW
INTO: Q > 0 System Absorbs Heat Heat --> Sys
OUT: Q < 0 System Releases Heat Sys --> Heat
Some common types of Heat Lost:
Solids or Liquids
Gas- Constant Pressure Process
Gas - Constant Volume Process
Gas - Constant Temperature Process
Gas - Adiabatic Process
INTERNAL ENERGY U
Energy Stored in a System at the Molecular Level.
The System's Thermal Energy -the Kinetic Energy of the atoms due to their random motion relative to the Center of Mass plus the binding energy (Potential Energy) that holds the atoms together.
U = Microscopic Energy contained in the System
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regards
Ramesh