High School

We appreciate your visit to Determine the vapor pressure of isooctane C8H18 at a temperature of 38 0 C given that its enthalpy of vaporization is 35 8 kJ mol. This page offers clear insights and highlights the essential aspects of the topic. Our goal is to provide a helpful and engaging learning experience. Explore the content and find the answers you need!

Determine the vapor pressure of isooctane (C8H18) at a temperature of 38.0°C, given that its enthalpy of vaporization is 35.8 kJ/mol and its normal boiling point is 98.2°C.

Answer :

Final Answer:

The vapor pressure of isooctane (C8H18) at a temperature of 38.0°C is approximately 25.27 kPa.

Explanation:

To determine the vapor pressure of isooctane at 38.0°C, we can use the Clausius-Clapeyron equation, which relates the vapor pressure of a substance to its enthalpy of vaporization, temperature, and its normal boiling point. The equation is as follows:

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

Where:

P1 is the vapor pressure at the normal boiling point (known).

P2 is the vapor pressure at the desired temperature (unknown).

ΔHvap is the enthalpy of vaporization (given as 35.8 kJ/mol).

R is the universal gas constant (8.314 J/(mol*K)).

T1 is the normal boiling point temperature (known as 98.2°C, which needs to be converted to Kelvin).

T2 is the desired temperature (38.0°C, which also needs to be converted to Kelvin).

Converting temperatures to Kelvin:

T1 = 98.2°C + 273.15 = 371.35 K

T2 = 38.0°C + 273.15 = 311.15 K

Now we can plug these values into the equation:

ln(P2/P1) = (-35.8 * 10^3 J/mol / (8.314 J/(mol*K))) * (1/311.15 K - 1/371.35 K)

Solving for ln(P2/P1):

ln(P2/P1) = -6986.87

Now, we can find P2/P1:

P2/P1 = e^(-6986.87)

P2 = P1 * e^(-6986.87)

P1 is the vapor pressure at the normal boiling point, which can be found in reference tables (for isooctane, it's around 29.9 kPa). Therefore:

P2 ≈ 29.9 kPa * e^(-6986.87)

P2 ≈ 25.27 kPa

So, the vapor pressure of isooctane at 38.0°C is approximately 25.27 kPa.

Learn more about isooctane

brainly.com/question/35909267

#SPJ11

Thanks for taking the time to read Determine the vapor pressure of isooctane C8H18 at a temperature of 38 0 C given that its enthalpy of vaporization is 35 8 kJ mol. We hope the insights shared have been valuable and enhanced your understanding of the topic. Don�t hesitate to browse our website for more informative and engaging content!

Rewritten by : Barada