Temperature states · pressure states · cp · R
Ideal-gas entropy change
Inputs
User-entered absolute temperature state; properties and process path are not inferred.
User-entered absolute temperature state; properties and process path are not inferred.
User-entered absolute pressure state; gas state and losses are not derived.
User-entered absolute pressure state; gas state and losses are not derived.
User-entered constant-pressure specific heat; temperature dependence and gas identity are not derived.
User-entered specific gas constant; gas composition and properties are not derived.
Results
Literal ideal-gas specific entropy changeΔs
497.68
J/(kg·K)Literal temperature contribution
696.61
J/(kg·K)Literal pressure contribution
198.93
J/(kg·K)Declared temperature ratio
2
1Δs = cp·ln(T₂/T₁) − R·ln(p₂/p₁)
A first-pass number, not a code check, certification, or approval. Read the method and its limits below. What this is and is not.
Nearby: Sensible heat · Heat-exchanger ΔTlm · Plane-wall conduction · Thermal radiation exchange
Method
Formula, when it applies, and when it does not
Apply NASA’s constant-specific-heat ideal-gas pressure-temperature entropy relation to state inputs without inferring a thermodynamic process or equipment behavior.
Δs = cp·ln(T₂/T₁) − R·ln(p₂/p₁)
When
- Ideal-gas relation
- Declared absolute temperature and pressure states
- No process-path or property model
Don’t
- This applies NASA’s constant-specific-heat ideal-gas pressure-temperature entropy relation only to user-declared state values. It does not determine gas properties, phase, process path, reversibility, heat or work transfer, state validity, isentropic efficiency, refrigeration, equipment, capacity, safety, suitability, or approval.