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# Topic 4 Block A

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### Topic 4 Block A

1. 1. Group 4: Solubility<br />Block A<br />Carolina Zarate<br />Jason Wang<br />Michael Yeh<br />
2. 2. Title<br />Introduction<br /> The Problem<br /> Basic Research<br /> Balanced Equation<br /> Previous Experiments<br /> Why?<br /> Hypothesis<br />Stella Model<br /> The Solvation Process<br /> Deriving the Equation<br /> The Dynamic Model<br /> Evaluating the Model<br />Procedure<br /> Materials<br /> Methods<br />Data Analysis<br /> Data<br /> PHS Block A Boxplots<br /> Overall Boxplots<br /> Graph Comparison<br />Analysis<br />Problems Encountered<br /> Conclusion<br />Sources<br />Introduction<br />
3. 3. Introduction<br />The Problem<br /><ul><li>General Question:</li></ul>What is the effect of temperature on solubility of salts?<br /><ul><li>Tested Question:</li></ul>What is the effect of temperature on the solubility of potassium nitrate at temperatures of 0oC, 25oC, and 60oC?<br />
4. 4. Introduction<br />Basic Research<br />Basic facts about Potassium nitrate, or KNO3<br />Potassium nitrate can<br />be dissolved in water<br />It is an orthorhombic crystal.<br />Its melting point<br />is 334oC<br />Its boiling point<br />is 400oC<br />
5. 5. Introduction<br />Balanced Equation<br />The equation for our experiment:<br />KNO3(s) + H2O(l) ->K+(aq) + NO3-(aq) + H2O(l)<br />The net ionic equation simplifies to:<br />KNO3 (s) ->K+ (aq) + NO3- (aq)<br />
6. 6. Introduction<br />Previous Experiments<br />Our research found sources created by other scientists working in this field:<br />Empirical data found in other researchers’ previous experiments<br />The data showed an exponential increase in solubility with temperature<br />
7. 7. Introduction<br />Why?<br />Real-world applications of the results gathered from our experiment include:<br /><ul><li>Solutions in cooking and food
8. 8. Solutions found in living organisms
9. 9. Industry, such as ore processing</li></li></ul><li>Introduction <br />Hypothesis<br />The solubility of potassium nitrate is expected to increase exponentially as temperature increases.<br /><ul><li>Other solids soluble in water follow similar trends
10. 10. A dynamic model in was created in Stella and used to predict the solubility at each temperature</li></li></ul><li>Title<br />Introduction<br /> The Problem<br /> Basic Research<br /> Balanced Equation<br /> Previous Experiments<br /> Why?<br /> Hypothesis<br />Stella Model<br /> The Solvation Process<br /> Deriving the Equation<br /> The Dynamic Model<br /> Evaluating the Model<br />Procedure<br /> Materials<br /> Methods<br />Data Analysis<br /> Data<br /> PHS Block A Boxplots<br /> Overall Boxplots<br /> Graph Comparison<br />Analysis<br />Problems Encountered<br /> Conclusion<br />Sources<br />Stella Model<br />
11. 11. Stella Model<br />The Solvation Process<br /><ul><li>When KNO3 and H2O form a solution, the KNO3 dissociates into K+ and NO3- ions.
12. 12. At equilibrium, a pair of ions will recombine for each pair that disassociates
13. 13. The solubility product constant for our solution is</li></ul>Ksp= [K+][NO3-]<br />NO3-<br />NO3-<br />NO3-<br />NO3-<br />NO3-<br />NO3-<br />K+<br />K+<br />K+<br />K+<br />K+<br />K+<br />Dissolving potassium nitrate<br />
14. 14. Stella Model<br />Deriving the Equation<br />Gibbs-Helmholtz Equation: G = H - T * S<br />Relationship between Ksp and G:<br />G = -R * T * ln(Ksp)<br />H - T * S = -R * T * ln(Ksp)<br />ln(Ksp) = (H - T * S) / (-R * T)<br />Ksp = e(S / R -H / (R * T))<br />H: Enthalpy change<br />S: Entropy change<br />G: Free energy change<br />T: Temperature (Kelvin)<br />R = 8.314 J/(mol*K)<br />
15. 15. Stella Model<br />Deriving the Equation<br />Ksp= [K+][NO3-] = x2<br />x2 = eS / R - H / (R * T)<br />x = Sqrt(eS / R - H / (R * T))<br />ICE box: x is the solubility<br />
16. 16. Stella Model<br />The Dynamic Model<br />The values for S and H were found in The CRC Handbook of Physics and Chemistry<br />
17. 17. Stella Model<br />The Dynamic Model<br />Predictions:<br />0°C:13 g KNO3<br />per 100 mL H2O.<br />25°C: 37.5 g KNO3 per 100 mL H2O.<br />60°C: 71.73 g KNO3 per 100 mL H2O.<br />
18. 18. Stella Model<br />Evaluating the Model<br />Reasons for the linear solubility curve:<br /><ul><li>Only one changing variable, T
19. 19. More accurate at lower temperatures
20. 20. To fix this, it would have been necessary to find the change in temperature</li></li></ul><li>Title<br />Introduction<br /> The Problem<br /> Basic Research<br /> Balanced Equation<br /> Previous Experiments<br /> Why?<br /> Hypothesis<br />Stella Model<br /> The Solvation Process<br /> Deriving the Equation<br /> The Dynamic Model<br /> Evaluating the Model<br />Procedure<br /> Materials<br /> Methods<br />Data Analysis<br /> Data<br /> PHS Block A Boxplots<br /> Overall Boxplots<br /> Graph Comparison<br />Analysis<br /> Problems Encountered<br /> Conclusion<br />Sources<br />Procedure<br />
21. 21. Procedure<br />Materials<br />1 PASCO Explorer GLX (#4)<br />1 GLX Temp Probe (Stainless Steel Chemical Resistant)<br />20 Weighing Boats<br />1 Analytical Scale<br />1 Glass Funnel<br />1 1000 mL Beaker<br />1 10 mL Graduated Cylinder<br />1 Vacuum Flask<br />4 50 mL Erlenmeyer Flasks<br />1 Hot Plate<br />1 Mixer (Separate from hot plate)<br />10 mL Tap Water (H2O) per Trial<br />6 g KNO3 per Trial<br />Ice: enough to fill a 1000 mL Beaker<br />1 Plastic Pipette<br />15 Filter Papers<br />1 Small Magnetic Stirrer Pill<br />1 Magnet to take out the Pill<br />
22. 22. Procedure<br />Methods<br />Measure 10 mL of tap water and pour into Erlenmeyer flask.<br />Put Erlenmeyer flask onto a hot plate and heat to 60oC. (Use GLX to measure temperature)<br />
23. 23. Procedure<br />Methods<br />Measure 6 g of potassium nitrate in a weighing boat on an analytical scale<br />Remove the Erlenmeyer flask from the hot plate<br />Pour the potassium nitrate and the magnetic stirrer into the Erlenmeyer flask<br />
24. 24. Procedure<br />Methods<br />Pay attention to the temperature as the KNO3 dissolves.<br />Allow the magnetic stirrer to run for 2-5 minutes<br />Remove the magnetic stirrer and temperature probe<br />
25. 25. Procedure<br />Methods<br />Place a filter paper into the funnel, and insert into the vacuum flask<br />Pour the contents of the Erlenmeyer flask through the filter paper<br />Remove the filter paper and place on the table to dry.<br />
26. 26. Procedure<br />Methods<br />Place an unused filter paper on the analytical scale and zero it<br />Place the dry paper with the potassium nitrate on the scale to weigh the undissolved solute<br />Subtract the weight from 6 g<br />
27. 27. Procedure<br />Methods<br />Repeat this process 4 more times<br />Repeat 1-15, but heat water to 25oC instead<br />Repeat 1-15, but use an ice bath to cool water to 0oC<br />Drying KNO3<br />Ice Bath<br />
28. 28. Title<br />Introduction<br /> The Problem<br /> Basic Research<br /> Balanced Equation<br /> Previous Experiments<br /> Why?<br /> Hypothesis<br />Stella Model<br /> The Solvation Process<br /> Deriving the Equation<br /> The Dynamic Model<br /> Evaluating the Model<br />Procedure<br /> Materials<br /> Methods<br />Data Analysis<br /> Data<br /> PHS Block A Boxplots<br />Overall Boxplots<br /> Graph Comparison<br />Analysis<br /> Problems Encountered<br /> Conclusion<br />Sources<br />Data & Analysis<br />
29. 29. Data & Analysis<br />Data<br /><ul><li>We did 15 trials, 5 trials at each temperature
30. 30. We used 10 mL of water and 6 g of KNO3 per trial, but we scaled our results up to 100 mL and 60 g</li></li></ul><li>Data & Analysis<br />Data<br />
31. 31. Data & Analysis<br />PHS Block A Boxplots<br />0°C<br />Median: 15.8<br />Minimum: 13.8<br />Maximum: 19.4<br />Interquartile Range: 3.25<br />25°CMedian: 23.1Minimum: 22.5Maximum: 23.5Interquartile Range: 0.8<br />60°CMedian: 41.2Minimum: 38.1Maximum: 43.3Interquartile Range: 3.75<br />
32. 32. Data & Analysis<br />Overall Boxplots<br />0°CMedian: 13.3Minimum: 2.40Maximum: 25.20Interquartile Range: 3.8375Outliers: 2.40 5.25 5.40 6.64 25.20 19.4<br />25°CMedian: 33.50Minimum: 13.23Maximum: 45.20Interquartile Range: 11.8Outlier: 13.23<br />60°CMedian: 74.75Minimum: 24.72Maximum: 123.00Interquartile Range: 63.92Outliers: none<br />
33. 33. Data & Analysis<br />Graph Comparison<br /><ul><li>Our data graph intersects overall data graph
34. 34. Large difference in 60°C data</li></li></ul><li>Data & Analysis<br />Analysis<br /><ul><li>Our low IQRs mean the data is very precise
35. 35. Mean and median are fairly close, meaning data is consistent
36. 36. Data did increase exponentially, but not exactly as predicted
37. 37. 0oC trials dissolved more than expected; room temperature heated the solution
38. 38. 60oC dissolved less than expected; room temperature cooled the solution</li></li></ul><li>Data & Analysis<br />Analysis<br /><ul><li>Overall results closely match results from professional experiments
39. 39. Lots of inconsistencies shown in the boxplots
40. 40. Much larger IQR for 60oC than our block alone
41. 41. More outliers for 0oC: 6 as opposed to 1 and none
42. 42. Variations in data due to different procedures
43. 43. Even with larger IQRs and more outliers, mean and medians of the 155 trials match our hypothesis closely</li></li></ul><li>Data & Analysis<br />Problems Encountered<br /><ul><li>Maintaining temperature: cooling to 0o and heating to 60oC
44. 44. Rate of dissolution: used a magnetic stirrer to accelerate process
45. 45. Transferring solution: wet residue stuck to sides of flask, used spatula to remove it
46. 46. Measuring remnants: wet filter paper was inconsistent, waited for the crystals to dry</li></li></ul><li>Data & Analysis<br />Conclusion<br />Hypothesis confirmed: the solubility did increase exponentially when the temperature increased.<br /><ul><li>155 trials not enough to definitively answer the question – it does provide solid evidence
47. 47. In the future, more data can be collected using same methods
48. 48. Possible variations:
49. 49. Change temperatures tested
50. 50. Use different salts instead of KNO3</li></li></ul><li>Sources<br />Austin Peay State University. (n.d.). Introduction. In Solubility and Thermodynamics of Potassium Nitrate. Retrieved from Department of Chemistry, Austin Peay State University website: http://www.apsu.edu/‌files/‌chemistry/‌Solubility_and_Thermodynamics_of_Potassium_Nitrate_RF9.pdf<br />Bender, H., & Francis, E. (2003). Dissolution Reactions. Retrieved April 5, 2011, from Clackamas Community College website: http://dl.clackamas.edu/‌ch105-03/‌dissolut.htm<br />Buthelezi, T., Dingrando, L., Hainen, N., Wistrom, C., & Zike, D. (2008). Chemistry: Matter and Change. Columbus, OH: Glencoe/‌McGraw-Hill.<br />Clark, J. (2005). Solubility Curves. In Solid-Liquid Phase Diagrams: Salt Solution. Retrieved from http://www.chemguide.co.uk/‌physical/‌phaseeqia/‌saltsoln.html<br />Debelius, B. B., Gómez-Parra, A., & Forja, J. (2009). Oxygen solubility in evaporated seawater as a function of temperature and salinity. Retrieved from EBSCOhost database. (43264914)<br />Determination of Saturation Temperature Method. (n.d.). Solubility of Salts. Retrieved April 5, 2011, from College of DuPage website: http://www.cod.edu/‌dept/‌chem/‌poc/‌Experiments/‌PotassiumNitrate-02/‌Solubility.htm#Intro<br />Grow, J. M. (1999, August). Heat of Solution. Retrieved April 5, 2011, from New Jersey Institute of Technology website: http://www-ec.njit.edu/‌~grow/‌Heatsolution/‌HeatofSolution.html<br />Lerner, E. K. L., & Lerner, B. W. (2008). Solubility. Retrieved April 5, 2011, from Gale Science in Context database. (CV2644032069 )<br />Lide, D. R. (Ed.). (2003-2004). CRC Handbook of Chemistry and Physics [PDF] (84th ed.).<br />Mierdel, K., & Keppler, H. (2004, August 5). Abstract. In The Temperature Dependence of Water Solubility in Enstatite. Retrieved from EBSCOhost database. (14964762)<br />Newton, D. E. (1999). Chemical Elements: From Carbon to Krypton: Vol. 3. P-Z (L. W. Baker, Ed.). Farmington Hills, MI: UXL.<br />Silberman, R. G. (1999). The Thermodynamics of Potassium Nitrate Dissolving in Water (H. D. Schreiber, Ed.) [Pamphlet]. Retrieved from http://cerlabs.brookscole.com/‌experiments/‌10875405126.pdf<br />Solubility Product Constants, Ksp. (n.d.). Retrieved April 20, 2011, from Purdue University website: http://www.chem.purdue.edu/‌gchelp/‌howtosolveit/‌equilibrium/‌solubility_products.htm#Solubilitypure<br />STELLA Models . (n.d.). Retrieved April 20, 2011, from Williamsport High School website: http://www.wcboe.k12.md.us/‌custom_pages/‌430/‌main_old/‌mvhs/‌stella/‌index.html<br />University of Virgina Physics Department. (2009). Temperature Effect on Solubility. Retrieved March 5, 2011, from University of Virginia website: http://galileo.phys.virginia.edu/‌education/‌outreach/‌8thgradesol/‌TempSolubility.htm<br />Zumdahl, S. S. (1989). Chemistry (2nd ed.). Lexington, Massachusetts: D.C. Heath and Company. doi:10.1021/‌ed066pA231.1<br />
51. 51. Any Questions?<br />