Vapour pressure correlation name check: The empirical equation log10 P = A − B/(t + C) for pure components is known as the ________ equation.
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AKistyakowsky equation
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BAntoine equation
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CKopp’s rule
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DTrouton’s rule
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ERedlich–Kwong equation
Answer
Correct Answer: Antoine equation
Explanation
Introduction / Context:Correlations for pure-component vapor pressures are used in VLE design and simulation. A widely used empirical fit is the Antoine equation, convenient over moderate temperature ranges.
Given Data / Assumptions:
- Equation form: log10 P = A − B/(t + C).
- P is often in mmHg or bar depending on parameterization; t is temperature (commonly °C).
Concept / Approach:Recognize the canonical form and its name. The Antoine equation is a three-parameter modification of the Clausius–Clapeyron relation that improves fitting accuracy across limited ranges.
Step-by-Step Reasoning:
Match form: log10 P vs 1/(t + C) with constants A, B, C → Antoine.Other listed items are unrelated: Kopp’s and Trouton’s are rules of thumb; Kistyakowsky is a different correlation family; Redlich–Kwong is an equation of state.Verification / Alternative check:Process simulators store Antoine constants for thousands of compounds, confirming the naming convention.
Why Other Options Are Wrong:
- They do not correspond to the given functional form for vapor pressure.
Common Pitfalls:Using Antoine constants outside their valid temperature range; mixing units for P without matching the fitted constants.
Final Answer:Antoine equation