Question

The vapor pressure of Substance X is measured at several temperatures:temperature (C) vapor pressure (atm)34 0.23644 0.29254 0.355Use this information to calculate the enthalpy of vaporization of X. Round your answer to 2 significant digits. Be sure your answer contains a correct unit symbol. Clears your work. Undoes your last action. Provides information about entering answers.

Answer 1

ΔHv = 17.04 KJ/mol

Step-by-step explanation:

T(°C) T(K) Pv(atm) 1/T(K) LnPv

34 307 0.236 0.00325733 - 1.4439

44 317 0.292 0.0031545 - 1.2310

54 327 0.355 0.003058 - 1.0356

Clausius-Clapeyron:

• δLnP/δT = ΔH/RT²

⇒ δLnP = ΔH/R (δT/T²)

∴ δT/T² = δ/δT(- 1/T )

⇒ δLnP/δT = - ΔH/R

Graphing: LnP vs 1/T

we get an ecuation that corresponds to a straight line:

y = - 2049.6x + 5.2331 ...... R² = 1

where the slope of this line is:

y = mx + b

⇒ m = - 2049.6 = - ΔH/R.....Clausius-Clapeyron

⇒ ΔH = (2049.6)(R)

∴ R = 8.314 E-3 KJ/mol.K

⇒ ΔHv = 17.04 KJ/mol