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# Final Presentation Ideal Solution 2

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• ### Final Presentation Ideal Solution 2

1. 1. Analysis of the Deviations from Ideality of a Methanol-Water System through Functions of Mixing Sarah Rudy Mark Sleeper David Watts Tyler Garrett
2. 2. Executive Summary <ul><li>Main objective included observing deviations from ideality of a methanol-water solution through heat of mixing, volume of mixing, and analyses of partial pressures of mixing. </li></ul><ul><li>Accomplished by varying molar fractions of methanol and water. </li></ul><ul><li>Used a calorimeter to observe heat outputs for exothermic reaction. </li></ul><ul><li>Used pycnometers to measure mass of liquid and calculate density changes of solutions. </li></ul><ul><li>Provided partial pressures of methanol and water at different mole fractions. </li></ul>
3. 3. Introduction <ul><li>What is an ideal solution? </li></ul><ul><ul><li>Interactions between solute and solvent molecules are the same as those between two identical molecules </li></ul></ul><ul><li>How does this translate to the experiment? </li></ul><ul><ul><li>Does not absorb or produce heat </li></ul></ul><ul><ul><li>Exhibits volume equal to the sum of the volume of its separate parts </li></ul></ul><ul><ul><li>Displays vapor pressure as a linear function of molar composition </li></ul></ul><ul><li>Extensive properties of a solution are directly proportional to the size of the system. </li></ul><ul><ul><li>X = n 1 * X 1 + n 2 * X 2 </li></ul></ul>
4. 4. Heat of Mixing
5. 5. Experimental <ul><li>Mixing of methanol and water in order to observe deviations from ideality. </li></ul>Water and Methanol Water and Water Methanol and Methanol
6. 6. Experimental (cont’d) <ul><li>Heat of Mixing </li></ul><ul><ul><li>CSC 2-Drop Calorimeter </li></ul></ul>
7. 7. Data and Results
8. 8. Data Acquired
9. 9. Literature Data: Comparison of Experimental Excess Molar Enthalpies To Simulation Data Vlcek, L.; Nezbeda, I. Excess Properties Of Aqueous Mixtures Of Methanol:  Simple Models Versus Experiment. Journal of Molecular Liquids 2007 ; pp 161.
10. 10. Data and Results (cont’d) <ul><li>Mixing water and methanol is exothermic . </li></ul><ul><li>Deviation from ideality increased as the solution approached 1:1 ratio of methanol and water. </li></ul>
11. 11. Modification 1 <ul><li>Objective </li></ul><ul><ul><li>How does varying the starting solution’s temperature affect the heat of mixing? </li></ul></ul>
12. 12. Modification 1 (cont’d)
13. 13. Modification 1(cont’d) <ul><li>Results </li></ul><ul><ul><li>At the higher temperature, the heat of mixing was closer to the ideal value. </li></ul></ul><ul><li>Explanation </li></ul><ul><ul><li>At an elevated temperature, the mixture acts more ideally. The molecules move faster and therefore have higher energy. </li></ul></ul><ul><ul><li>This also means that more space between the molecules is available. The solution mixes faster and easier than at lower temperatures </li></ul></ul>
14. 14. Modification 2 <ul><li>Objective </li></ul><ul><ul><li>To show how intermolecular forces affect the ideality of the volume of mixing and heat of mixing. </li></ul></ul><ul><ul><li>To show this, isopropanol was substituted for methanol in the mixture with H2O </li></ul></ul>Methanol Isopropanol
15. 15. Modification 2(cont’d) Water and Isopropanol Mixture Water and Methanol Mixture
16. 16. Modification 2(cont’d)
17. 17. Modification 2(cont’d) <ul><li>Results </li></ul><ul><ul><li>The Isopropanol and water mixture proved to be closer to ideal than the mixture of methanol and water. </li></ul></ul><ul><ul><li>Isopropanol and water contain stronger molecular forces than do methanol and water. Isopropanol and water more readily mix making it the more ideal solution </li></ul></ul><ul><ul><li>Isopropanol is more polar </li></ul></ul>
18. 18. Volume of Mixing
19. 19. Experimental <ul><li>Seven solutions were prepared </li></ul><ul><ul><li>Covers a range of mole ratios </li></ul></ul>Mole Ratio Methanol Mole Ratio Water 1 0 .8 .2 .6 .4 .4 .6 .2 .8
20. 20. Experimental <ul><li>Volume of mixing is dependant upon density </li></ul><ul><ul><li>Ideal Volume of Mixing: </li></ul></ul><ul><ul><li>Real Volume of Mixing: </li></ul></ul>
21. 21. Experimental <ul><li>Pycnometers were used </li></ul><ul><ul><li>Allow bubbles to escape </li></ul></ul><ul><ul><li>Accurate density measurement </li></ul></ul>
22. 22. Experimental <ul><li>Constant temperature is needed. </li></ul><ul><ul><li>Water bath at 25 °C was used </li></ul></ul><ul><li>The mass of each solution could then be calculated . </li></ul>
23. 23. Experimental <ul><li>Density of mixture could then be calculated: </li></ul>Mole Fraction of Water Density of Solution (g/mL )   0 0.790   0.2   0.846   0.4 0.868   0.6   0.905   0.8   0.942
24. 25. Literature Data: Comparison of Experimental Volume of Mixings to Simulation Data
25. 26. Partial Pressure of Mixing
26. 27. Partial Pressure of Mixing
27. 28. Partial Pressure of Mixing (Cont.) <ul><li>Due to the exothermic nature of the mixing, the partial pressure of mixing deviated from ideality. </li></ul><ul><ul><li>Because of an increased temperature of the system, components vaporized to a larger extent than if the solution were ideal. </li></ul></ul>
28. 29. Conclusion <ul><li>The mixing of methanol and water is non-ideal </li></ul><ul><ul><li>Heat is evolved upon mixing </li></ul></ul><ul><ul><li>Volume upon mixing does not equal the sum of the volumes of the components </li></ul></ul><ul><ul><li>A non-linear relationship was observed between the partial pressure of methanol and its mole fraction. </li></ul></ul><ul><li>Modifications: </li></ul><ul><ul><li>An increase in temperature causes the mixture to behave more ideally with regards to heat of mixing. </li></ul></ul><ul><ul><li>The size of the alcohol effects the ideality of the mixture. </li></ul></ul>
29. 30. References <ul><li>1.   McQuarrie, D.A.; Simon, J.D.  Physical Chemistry: a Molecular Approach .  University Science Books: Sausalito, CA, 1997; p 638. </li></ul><ul><li>2.    Block Diagram Of the CSC Model 4400 Isothermal Microcalorimeter ; May 1998; 24 Sept. 2008 < http://www.devicelink.com/mpb/archive/98/05/9805b50a.gif >. </li></ul><ul><li>3.   Material Safety Data Sheet; 14 March 2001; Iowa State University; 17 Sept. 2008 < http://avogadro.chem.iastate.edu/MSDS/Methanol.htm >. </li></ul><ul><li>4.    Perrot, Pierre.   A to Z of Thermodynamics .  Oxford University Press: Oxford, 1998. </li></ul><ul><li>5.    Liquid (State of Matter): Endothermic and Exothermic Solutions ; Britannica Online Encyclopedia Website; 1 Oct. 2008 < http://www.britannica.com/EBchecked/topic/343026/liquid > </li></ul><ul><li>6.    Vlcek, L.; Nezbeda, I. Excess Properties Of Aqueous Mixtures Of Methanol:  Simple Models Versus Experiment. Journal of Molecular Liquids 2007 ; pp 131-132, 158-162. </li></ul><ul><li>7.    Harris, Daniel C. Quantitative Chemical Analysis, 7th ed.; W.H. Freeman and Company: New York, 2007; p 65. </li></ul><ul><li>8.    Ideal Solution ; Britannica Online Encyclopedia Website; 1 Oct. 2008 < http://www.britannica.com/EBchecked/topic/281790/ideal-solution >. </li></ul>