INTRODUCTION: The vapor pressure of a species is a measure of its volatility. If

Question

INTRODUCTION:

The vapor pressure of a species is a measure of its volatility. If a substance has a high vapor pressure at a given temperature, its volatility is greater (that is, more of that substance is in the gas phase). It is important to know vapor pressure for many engineering applications, especially relating to separation of two substances. Two equations that may be used to estimate the vapor pressure of pure substances are the Clausius-Clapeyron equation (1) and the empirical Antoine equation

where p* is the vapor pressure of the pure species in mm Hg, is the specific enthalpy of the species in question, R is the universal gas constant, T is the temperature in Kelvin, and D is a species-specific constant; and

log10p*=A-B/T-C

where p* is the vapor pressure of the pure species in bar, T is the temperature in Kelvin, and A, B, and C are species-specific constants.

For this program, estimate the pressure for benzene at any temperature. Define D in the Clausius-Clapeyron equation as a symbolic constant in your program, and use 18.69. Also define A, B, and C in the Antoine equation as symbolic constants in your program and use the values 4.01814, 1203.835, and -53.226, respectively.

ASSIGNMENT:

Write a C program that will allow the user to enter the temperature T in °C. Once the user enters the initial value, the program will compute the vapor pressure using both equations. Before performing the calculations, you will need to convert from °C to degrees Kelvin. Use the following equation to help you.

Report both vapor pressures in bar. To convert from mm Hg to bar, use the following relation:

As a hint, you can use the exp() function to return the value of e raised to the ()th power.

Your program output will look like the illustration shown on the next page. Use your PC’s cursor to determine the horizontal and vertical spacing for the output format.

OUTPUT FORMAT:

********************************************

               VAPOR PRESSURE                

Enter temperature in degrees C: x

RESULTS

Temperature                = xxx.xx K

Vapor Pressure:

By Clausius-Clapeyron      = x.xxxx bar

By Antoine                 = x.xxxx bar

********************************************

Explanation / Answer

#include<stdio.h>

#include<conio.h>

int main() {

    float fahren, celsius;

    printf("Enter the temperature in celsius ");

    scanf("%f", &celsius);

    /* convert celsius to fahreneheit

  * Multiply by 9, then divide by 5, then add 32

  */

    fahren =(9.0/5.0) * celsius + 32;

    printf("%.2fC is equal to %.2fF ", celsius, fahren);

getch();

return 0;

}

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