Chapter 18, Problem 68GQ

### Chemistry & Chemical Reactivity

10th Edition
John C. Kotz + 3 others
ISBN: 9781337399074

Chapter
Section

### Chemistry & Chemical Reactivity

10th Edition
John C. Kotz + 3 others
ISBN: 9781337399074
Textbook Problem

# Estimate the vapor pressure of ethanol at 37 °C using thermodynamic data. Express the result in millimeters of mercury.

Interpretation Introduction

Interpretation:

The vapour pressure of ethanol at 37 °C should be estimated using thermodynamic data which then has to be expressed in millimeters of mercury.

Concept introduction:

The vapor pressure of a substance is related to its enthalpy of vaporisation by the

expression,

ln(p2p1)=ΔHvapR(1T11T2)

Here, p1 and p2 are the vapour pressures at two different temperatures T1 and T2.

This equation is known as Clausius-Clapeyron equation and is used to estimate the vapour pressure of a substance at a particular temperature.

Explanation

The vapor pressure of ethanol at 37 °C is calculated below.

The Appendix L referred for the values of standard enthalpies of ethanol to calculate the value of ΔHvap.

The given reaction is,

C2H5OH(l)C2H5OH(g)

The ΔHvap for the above reaction is,

ΔHvap=(235.3 kJ/mol)(277.0 kJ/mol)=41.7 kJ/mol=41700 J/mol

The normal boling point of ethanol is 78 °C under the standard condition of pressure of 760 mmHg.

Thus,

The value of T1 is,

T1=37+273=310 K

The value of T2 is,

T2=78+273=351 K

The value of p2 is 760 mmHg

### Still sussing out bartleby?

Check out a sample textbook solution.

See a sample solution

#### The Solution to Your Study Problems

Bartleby provides explanations to thousands of textbook problems written by our experts, many with advanced degrees!

Get Started