The Clausius-Clapeyron Equation for Pressure calculator estimates the vapor pressure of a liquid at a certain temperature when the vapor pressure at another temperature is known.
INSTRUCTIONS: Choose units and enter the following:
- (P1) Vapor Pressure 1
- (ΔHvap) Molar Enthalpy of Vaporization
- (T1) Temperature 1 (corresponds with P1)
- (T2) Temperature 2
Pressure (P2): The calculator returns the vapor pressure at temperature T2 in atmospheres. However, the pressure can be automatically converted to other pressure units (.e.g., pascals) via the pull-down menu.
The Math
The Clausius-Clapeyron Equation is as follows:
`ln((P_1)/(P_2)) = -(DeltaH_(vap))/R * (1/T_1 - 1/T_2)`
where R is the ideal gas constant (8.314 J/mol*K)
This calculator solves the above equation for P2. Therefore, the Clausius-Clapeyron equation for final pressure is:
`P_2 = P_1 * e^((DeltaH_"vap")/R (1/T_1 - 1/T_2))`
where:
- P2 = Pressure at T2
- P1 = Pressure at T1
- T1 = Temperature 1
- T2 = Temperature 2
- R = Ideal Gas Constant
Clausius-Clapeyron Equation Calculators
Chemistry Calculators
- R - Gas Constant: 8.3144626181532 J/(K⋅mol)
- Boyle's Law Calculator: P1 • V1 = P2 • V2
- Charles Law Calculator: V1• T2 = V2 • T1
- Combined Gas Law Calculator: P•V / T= k
- Gay-Lussac Law: T1•P2 =T2•P1
- Ideal Gas Law: P•V = n•R•T
- Bragg's Law: n·λ = 2d·sinθ
- Hess' Law: ΔH0rxn=ΔH0a+ΔH0b+ΔH0c+ΔH0d
- Internal Energy: ΔU = q + ω
- Activation Energy: Ea = (R*T1⋅T2)/(T1 - T2) ⋅ ln(k1/k2)
- Arrhenius Equation: k = AeE_a/(RT)
- Clausius-Clapeyron Equation: ln(P2/P1) = (ΔHvap)/R * (1/T1 - 1/T2)
- Compressibility Factor: Z = (p*Vm)/(R*T)
- Peng-Robinson Equation of State: p = (R*T)/(Vm - b) - (a*α)/(Vm2 + 2*b*Vm - b2)
- Reduced Specific Volume: vr = v/(R* Tcr / Pc)
- Van't Hoff Equation: ΔH0 = R * ( -ln(K2/K1))/ (1/T1 - 1/T2)
Supplemental Materials
UCDavis ChemWiki: Clausius-Clapeyron Equation
YouTube: Find the Vapour Pressure (Clausius-Clapeyron Equation)
References
Whitten, et al. "Chemistry" 10th Edition. Pp. 467