Organic Chemistry Problem Set Solutions by Dr. M. Masykuri
Explore the solutions to vapor pressure and heat of vaporization problems in organic chemistry with detailed explanations provided by Dr. M. Masykuri from the Teacher Training and Education Faculty at Sebelas Maret University. Learn how to apply the Clausius-Clapeyron Equation to calculate enthalpy of vaporization for various compounds. Enhance your understanding of physical chemistry concepts through practical examples and step-by-step solutions.
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Kimia Fisika 2 Problem Set Persamaan Clapeyron dan Clausius-Clapeyron Dr. M. Masykuri, M.Si. Dr. M. Masykuri, M.Si. Chemistry Education Study Program Teacher Training and Education Faculty Sebelas Maret University (UNS) Website: http://mmasykuri.wordpress.com, email: mmasykuri@yahoo.com Teacher Training and Education Faculty Sebelas Maret University 4/19/2025 1 M. Masykuri_Phisical Chemistry 2 Solo, Feb 2020 Feb, 2020
Problem Set #1 Problem #1: Determine Hvap for a compound that has a measured vapor pressure of 24.3 torr at 273 K and 135 torr at 325 K. Teacher Training and Education Faculty Sebelas Maret University M. Masykuri_Phisical Chemistry 2 Feb, 2020
Problem Set #1 Solution #1: 1) Let us use the Clausius-Clapeyron Equation: with the following values: P1 = 24.3 torr T1 = 273 K P2 = 135 torr T2 = 325 K 2) Set up equation with values: ln (135/24.3) = (x / 8.31447) (1/273 -1/325) 1.7148 = (x / 8.31447) (0.00058608) 1.7148 = 0.000070489x x = 24327 J/mol = 24.3 kJ/mol Teacher Training and Education Faculty Sebelas Maret University M. Masykuri_Phisical Chemistry 2 Feb, 2020
Problem Set #2 Problem #2: A certain liquid has a vapor pressure of 6.91 mmHg at 0 C. If this liquid has a normal boiling point of 105 C, what is the liquid's heat of vaporization in kJ/mol? Teacher Training and Education Faculty Sebelas Maret University M. Masykuri_Phisical Chemistry 2 Feb, 2020
Problem Set #2 Solution #2: 1) Let us use the Clausius-Clapeyron Equation: ln (P1 / P2) = ( H / R) (1/T2 - 1/T1) with the following values: P1 = 6.91 mmHg T1 = 0 C = 273.15 K P2 = 760.0 mmHg T2 = 68.73 C = 378.15 K 2) Set up equation with values: ln (6.91/ 760) = (x / 8.31447) (1/378.15 - 1/273.15) -4.70035 = (x / 8.31447) (-0.0010165) 4.70035 = 0.00012226x (notice we got rid of the negative signs) x = 38445 J/mol = 38.4 kJ/mol Teacher Training and Education Faculty Sebelas Maret University M. Masykuri_Phisical Chemistry 2 Feb, 2020
Problem Set #3 Problem #3: Carbon tetrachloride has a vapor pressure of 213 torr at 40.0 C and 836 torr at 80.0 C. What s the enthalpy of vaporization in kJ/mol? Teacher Training and Education Faculty Sebelas Maret University M. Masykuri_Phisical Chemistry 2 Feb, 2020
Problem Set #3 Solution #3: 1) Let us rearrange the Clausius-Clapeyron Equation: ln (P1/P2) = (- Hvap/R) x (1/T1 - 1/T2) Hvap = [-R x ln (P1/P2)] / (1/T1 - 1/T2) 2) Insert values and solve: Hvap = [(-8.314 J/mole K) x ln (213 torr / 836 torr)] / (1/313.15 K - 1/353.15 K) Hvap = 31.4 kJ/mole Teacher Training and Education Faculty Sebelas Maret University M. Masykuri_Phisical Chemistry 2 Feb, 2020
Problem Set #4 Problem #4: The molar enthalpy of vaporization of hexane (C6H14) is 28.9 kJ/mol, and its normal boiling point is 68.73 C. What is the vapor pressure of hexane at 25.00 C? Teacher Training and Education Faculty Sebelas Maret University M. Masykuri_Phisical Chemistry 2 Feb, 2020
Problem Set #4 Solution #4: 1) Let us use the Clausius-Clapeyron Equation: ln (P1 / P2) = - ( H / R) (1/T1 - 1/T2) with the following values: P1 = x T1 = 25.00 C = 298.15 K P2 = 760.0 mmHg T2 = 68.73 C = 341.88 K 2) Set up equation with values: ln (x / 760) = - (28900 / 8.31447) (1/298.15 -1/341.88) ln (x / 760) = - 1.4912 x /760 = 0.2251 x = 171 torr the vapor pressure of a substance at its normal boiling point is 760 mmHg. Not indicating the above in this type of question is common. You have been warned! Comment: note that no pressure is given with the normal boiling point. This is because, by definition, Teacher Training and Education Faculty Sebelas Maret University M. Masykuri_Phisical Chemistry 2 Feb, 2020
Problem Set #5 Problem #5: What is the vapor pressure of benzene at 25.5 C? The normal boiling point of benzene is 80.1 C and its molar heat of vaporization is 30.8 kJ/mol. Answer in units of atm Teacher Training and Education Faculty Sebelas Maret University M. Masykuri_Phisical Chemistry 2 Feb, 2020
Problem Set #5 Solution #5: 1) Let us use the Clausius-Clapeyron Equation: ln (x / 1.00) = (30800 / 8.31447) (1/353.25 -1/298.65) Comment: I used the form of the equation shown, I assigned the unknown value to be associated with P2. That puts x in the numerator and a 1.00 in the denominator, making my calculation a bit easier. 2) Let us calculate: ln (x / 1.00) = (3704.385) (-0.000517545) ln x = -1.9172 x = 0.147 atm Comment: I used 273.15 to convert Celsius to Kelvin. It's normal to use 273. I just decded to walk on the wild side for a moment. Teacher Training and Education Faculty Sebelas Maret University M. Masykuri_Phisical Chemistry 2 Feb, 2020
Problem Set #6 Problem #6: The normal boiling point of Argon is 83.8 K and its latent heat of vaporization is 1.21 kJ/mol. Calculate its boiling point at 1.5 atmosphere. Teacher Training and Education Faculty Sebelas Maret University M. Masykuri_Phisical Chemistry 2 Feb, 2020
Problem Set #6 Solution #6: 1) Let us use the Clausius-Clapeyron Equation: ln (P1 / P2) = - ( H / R) (1/T1 - 1/T2) with the following values: P1 = 1.0 atm T1 = 83.8 K P2 = 1.5 atm T2 = x 2) Set up equation with values: ln (1.0/ 1.5) = - (1210 / 8.31447) (1/83.8 - 1/x) 0.405465 = 145.53 (0.011933 - 1/x) 0.405465 = 0.17366 minus 145.53 / x 0.231805 = -145.53 / x Teacher Training and Education Faculty Sebelas Maret University M. Masykuri_Phisical Chemistry 2 Feb, 2020
Problem Set #7 Problem #7: Chloroform, CHCl3has a vapor pressure of 197 mmHg at 23.0 C, and 448 mmHg at 45.0 C. Estimate its heat of vaporization and normal boiling point. Teacher Training and Education Faculty Sebelas Maret University M. Masykuri_Phisical Chemistry 2 Feb, 2020
Problem Set #7 Solution #7: 1) Let us use the Clausius-Clapeyron Equation: ln (P1 / P2) = - ( H / R) (1/T1 - 1/T2) with the following values: P1 = 197 mmHg T1 = 296 K P2 = 448 mmHg T2 = 318 K 2) Set up equation to solve for the enthalpy of vaporization: ln (197 / 448) = - (x / 8.31447) (1/296 minus 1/318) x = 29227.66 J = 29.2 kJ 3) Let us use the Clausius-Clapeyron Equation: ln (P1 / P2) = - ( H / R) (1/T1 - 1/T2) with the following values: P1 = 760 mmHg T1 = x P2 = 448 mmHg T2 = 318 K 4) Set up equation to solve for the normal boiling point: ln (760 / 448) = - (29227.66 / 8.31447) (1/x minus 1/318) 0.5285252 = - 3515.2764 (1/x minus 1/318) 0.5285252 = 11.05433 minus (3515.2764 / x) 10.5258048 = 3515.2764 / x = 334 K Teacher Training and Education Faculty Sebelas Maret University x M. Masykuri_Phisical Chemistry 2 Feb, 2020
Problem Set #8 Problem #8: A 5.00 L flask contains 3.00 g of mercury. The system is at room temperature of 25.0 C. By how many degrees should we increase the temperature of the flask to triple the mercury vapor pressure. The enthalpy of vaporization for mercury is 59.11 kJ/mol? Teacher Training and Education Faculty Sebelas Maret University M. Masykuri_Phisical Chemistry 2 Feb, 2020
Problem Set #8 Solution #8: 1) Let us use the Clausius-Clapeyron Equation with the following values: P1 = 1 T1 = 298 K P2 = 3 T2 = x Comment: I don't care what the actual vapor presssure value is at either temperature. I just care that it triples in value from P1 to P2. Wy can I do this? Because I will be using a ratio of P2 to P1. I only care that that ratio is 3. 3) Set up equation with values: ln (3/1) = (59110 / 8.31447) (1/298 minus 1/x) 1.0968 = 7109.2926 (1/298 minus 1/x) 1.0968 = 23.8567 minus 7109.2926/x) x = 312.4 K = 39.4 C Teacher Training and Education Faculty Sebelas Maret University M. Masykuri_Phisical Chemistry 2 Feb, 2020
Soal Latihan 1. Ilustrasikan dengan grafik versus T kenyataan bahwa Sfus dan Ssub dijamin selalu positif dimana fase padat paling stabil pada temperatur rendah 2. Tekanan uap bromium cair pada 9,3oC adalah 100 atm. Jika panas penguapan adalah 30910 J/mol, hitung titik didih bromium! Teacher Training and Education Faculty Sebelas Maret University M. Masykuri_Phisical Chemistry 2 Feb, 2020
Soal Latihan 3. Naftalena, C10H8, meleleh pada 80oC. Jika tekanan uap zat cair adalah 10 atm pada 85,8oC dan 40 atm pada 119,3oC, dan untuk zat padat adalah 1 atm, hitung a. Huap zat cair, titik didih, dan Suap pada Tb b. tekanan uap pada titik leleh Teacher Training and Education Faculty Sebelas Maret University M. Masykuri_Phisical Chemistry 2 Feb, 2020
Soal Latihan 4. Untuk ammonia t/oC p/atm Plot data ln p versus 1/T untuk menentukan Huap, dan titik didih normal 4,7 5 25,7 50,1 78,9 10 20 40 5. Iodium mendidih pada 183oC; tekanan uap zat cair pada 116,5 oC adalah 100 atm. Jika Hofus= 15,65 J/mol dan tekanan uap zat padat adalah 1 atm pada 38,7 oC, hitung: a. Houap, dan Souap b. temperatur dan tekanan titik tripel Teacher Training and Education Faculty Sebelas Maret University M. Masykuri_Phisical Chemistry 2 Feb, 2020
References http://www.chm.bris.ac.uk/~chdms/Teaching/Chemical_In teractions/page_11.htm http://www.chemteam.info/GasLaw/Clasius-Clapeyron- Equation.html Teacher Training and Education Faculty Sebelas Maret University M. Masykuri_Phisical Chemistry 2 Feb, 2020
Sekian Teacher Training and Education Faculty Sebelas Maret University M. Masykuri_Phisical Chemistry 2 Feb, 2020
UK Hari Kamis, tanggal 24 Maret 2016 jam 7 -9 pagi, materi: Pengantar dan Transisi fasa zat murni; open book/laptop. Teacher Training and Education Faculty Sebelas Maret University M. Masykuri_Phisical Chemistry 2 Feb, 2020
