How Do You Calculate the Vapor Pressure of Water at Different Temperatures?

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SUMMARY

The vapor pressure of water at 59.8°C can be calculated using the Clausius-Clapeyron equation. The initial vapor pressure at 25.0°C is 23.8 torr, which converts to 0.0313 atm. The heat of vaporization is 43.9 kJ/mol, equivalent to 43900 J/mol, and the gas constant R is 8.31 J/(mol·K). The calculations provided in the forum indicate a potential typo in the heat of vaporization, which may lead to incorrect results.

PREREQUISITES
  • Understanding of the Clausius-Clapeyron equation
  • Knowledge of unit conversions between torr and atm
  • Familiarity with thermodynamic concepts such as heat of vaporization
  • Basic proficiency in algebra for solving equations
NEXT STEPS
  • Review the Clausius-Clapeyron equation in detail
  • Practice converting between different pressure units, specifically torr and atm
  • Investigate the implications of heat of vaporization on vapor pressure calculations
  • Explore common errors in thermodynamic calculations and how to avoid them
USEFUL FOR

Chemistry students, educators, and professionals involved in thermodynamics or physical chemistry who need to calculate vapor pressures at varying temperatures.

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Homework Statement


The vapor pressure of water at 25.0 C is 23.8 torr, and the heat of vaporization is 43.9 kJ/mol. What is the vapor pressure (atm) of water at 59.8C?

Homework Equations


Clausius-Clapeyron equation.
ln(P2/P1)=(ΔH/R)((1/T1)-(1/T2))

The Attempt at a Solution



P2=?
P1=23.8 torr = .031315789 atm
ΔH=43.9 KJ/mol=43900 J/mol
R= 8.31 (J)/(mol∙K)
T1=25.0°C=298 K
T2=59.8°C=332.8 K

plugged into the equation and keep getting the wrong answer.

Can someone please help.

ln(p2) - ln(.031315789) = -(439005)/(8.31) * [(1/332.8) - (1/298)]

HELP idk what i did wrong
 
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Atm is not KMS units
 
flatmaster said:
Atm is not KMS units
That shouldn't matter as long as P1 and P2 have the same units.

The setup looks good, but it does look like the calculations have a typo in the heat of vaporization though.
 
Last edited:

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