Question

**1a**. From the following vapor
pressure data for **octane**, an estimate of the molar
heat of vaporization of
**C _{8}H_{18}**
is kJ/mol.

P, mm Hg | T, Kelvins |

100 |
339 |

400 |
377 |

**1b.**

The normal boiling point of liquid **chloroform**
is **334** K. Assuming that its molar heat of
vaporization is constant at **29.9** kJ/mol, the
boiling point of **CHCl _{3}** when the
external pressure is

**1c.**

The vapor pressure of liquid **butanol**,
**C _{4}H_{9}OH**, is

A sample of

Only butanol vapor will be present.

Some of the vapor initially present will condense.

The pressure in the container will be 100. mm Hg.

Liquid butanol will be present.

No condensation will occur.

Answer #1

1a.

Recall that in equilibrium; especially in vapor-liquid equilibriums, we can use Clasius Clapyeron combination equation in order to relate two points in the same equilibrium line.

The equation is given as:

ln(P2/P1) = -dHvap/R*(1/T2-1/T1)

Where

P2,P1 = vapor pressure at point 1 and 2

dH = Enthalpy of vaporization, typically reported in kJ/mol, but we need to use J/mol

R = 8.314 J/mol K

T1,T2 = Saturation temperature at point 1 and 2

Therefore, we need at least 4 variables in order to solve this.

Substitute all known data:

ln(P2/P1) = -dHvap/R*(1/T2-1/T1)

Change negative signs

ln(P2/P1) = dHvap/R*(1/T1-1/T2)

ln(400/100) = dHvap/8.314*(1/(339) - 1/(377))

dHvap =38763.495 = 38.76 kJ/mol

1b

again, use clasius equation

ln(P2/P1) = dHvap/R*(1/T1-1/T2)

ln(1.34/1) = 29900/8.314*(1/(334 - 1/T)

T = (-ln(1.34/1) *8.314/29900+1/(334) )^-1

T = 343 K = 70 °C

The vapor pressure of liquid butanol,
C4H9OH, is
100. mm Hg at 343 K.
A sample of C4H9OH is placed
in a closed, evacuated 533 mL container at a
temperature of 343 K. It is found that all of the
C4H9OH is in the vapor phase
and that the pressure is 48.0 mm Hg. If the volume
of the container is reduced to 391 mL at constant
temperature, which of the following statements are correct?
Choose all that apply.
The...

The vapor pressure of liquid antimony is 400 mm Hg at 1.84×103
K. Assuming that its molar heat of vaporization is constant at 115
kJ/mol, the vapor pressure of liquid Sb is mm Hg at a temperature
of 1.80×103 K.

The vapor pressure of liquid lead is 400 mm Hg at 1.90×10^3 K.
Assuming that its molar heat of vaporization is constant at 181
kJ/mol, the vapor pressure of liquid Pb is________ mm Hg at a
temperature of 1.92×10^3 K

1) The vapor pressure of liquid bromoethane,
C2H5Br, is
100. mm Hg at 263 K. A
0.134 g sample of liquid
C2H5Br is placed in a
closed, evacuated 320. mL container at a
temperature of 263 K.
Assuming that the temperature remains constant, will all of the
liquid evaporate? _____yes/ no
What will the pressure in the container be when equilibrium is
reached? _______mm Hg
2) The vapor pressure of liquid acetone,
CH3COCH3, is
100. mm Hg at 281 K....

Water has a vapor pressure of 31.8 mm Hg at 30°C and a heat of
vaporization of 40.657 kJ/mol. Using the Clausius-Clapeyron
equation given below, determine the vapor pressure of water at
98°C.
______ mm Hg

Weight of flask and cover 128.7g
Weight of flask with vapor 129.4g
Pressure of vapor, mm Hg 760
Pressure of, atm 1
Mass of water in flask 250g
Temperature of water in flask (boiling water) =92c
Temperature of vapor in K= 92C+273=365K
Temperature of water in the flask= 25t
the volume of vapor in the flask 250 ML
Using the volume of the flask (in liters) the temperature of the
boiling-water bath (in kelvins), and the barometric pressure (in
atmospheres),...

Estimate the heat of vaporization (kJ/mol) of benzene at a
pressure of 120 mm Hg, using each of the following correlations and
data: (a) The heat of vaporization at the normal boiling point
given in Table B.1, the boiling point at 120 mm Hg as determined
from the Antoine equation, and Watson’s correction. Provide your
answer with three significant figures.

1) The vapor pressure of liquid heptane,
C7H16, is
40.0 mm Hg at 295 K.
A sample of C7H16 is
placed in a closed, evacuated container of constant volume at a
temperature of 450 K. It is found that all of the
C7H16 is in the vapor phase
and that the pressure is 74.0 mm Hg. If the
temperature in the container is reduced to 295 K,
which of the following statements are correct? chosse all that
apply.
A) Some...

Chloroform, CHCl3, a
volatile liquid, was once used as an anesthetic but has been
replaced by safer compounds. Chloroform has a normal
boiling point at 61.7 °C (1atm) and has a heat of
vaporization of 31.4 kJ/mol. What is its vapor pressure at 25.0
°C.

The vapor pressure of a liquid is 36.1 mmHg at 24oC.
The enthalpy of vaporization of the liquid is 10.2 KJ/mol. What is
the normal boiling point of the liquid?

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 2 minutes ago

asked 2 minutes ago

asked 22 minutes ago

asked 29 minutes ago

asked 37 minutes ago

asked 44 minutes ago

asked 44 minutes ago

asked 48 minutes ago

asked 55 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago