Freezing pointsChemistryExperimental InvestigationErin Chapman640 W. Scott St. Chicago, IL 60610Grade 811/21/17Table of Contents Acknowledgments Page 3Purpose and Hypothesis Page 4Review Of Literature Page 5-8Materials and Procedure Page 9Results Page 10-11Conclusion, Reflection, Application Page 12-13Reference List Page 14-15AcknowledgmentsI would like to thank my parents for buying all the supplies for me. I would also like to individually thank all the students that helped me with my project, and a large piece of gratitude goes to my dad. He helped me set up and complete the whole experiment while also being my photographer. Purpose,Hypothesis and Testable Question Testable QuestionHow does the change in solute affect the freezing point of water?Hypothesis When the Solutes start to freeze it will take about 15 minutes on average, because if a water tumbler takes 3 hours to freeze a small amount with a solute should be a fraction of a time. Meaning that salt will freeze faster because the sodium in salt will help it freeze faster.Purpose The purpose of this project was to figure out how fast different solutes would freeze. This project also including new scientific terms I was not familiar with for example Molality and Van’t Hoff Factor. These also added to the purpose which overall was to learn more about freezing points. This project helped me understand different formulas such as Molality(moles/kg)=Moles(mol)Solute/Kilograms(kg)Solvent and ?T=Kf×m×i. Learning new skills like this will help in the future. In addition to learning new terms I also found out how quickly water can freeze when things are added to it. Overall this project has been a huge help in my understanding toward freezing points. Review of Literature During this project, there were always two large questions. How does salt affect the freezing point and how does sugar affect the freezing point? These are very broad questions and along the way, other questions will come about considering how far this topic can lead therefore in order to answer them research will have to be involved. Throughout this experiment freezing point of water will be mentioned continuously so what is the freezing point exactly? The freezing point is the transition of when water turns to ice this happens at a certain temperature 32 degrees Fahrenheit or 0 degrees Celsius. “The typical freezing point of fresh water is 0° Celsius 32° Fahrenheit. Generally, water molecules are composed of hydrogen and water molecules and they have bonded together into a crystalline structure ice.” (http://www.worldofchemicals.com/558/chemistry-articles/how-does-salt- lower- the-freezing-point-of-water.html, Data Research Analysis, 2017) This shows that when water turns to ice its a change in matter caused by the temperature. Which leads to why it can be altered because the temperature can always change and fluctuate. When a substance is added it can really take a toll on how the freezing point takes place. “While pure water freezes at 0°C (32°F), salt water needs to be colder before it freezes and so it usually takes longer to freeze. The more salt in the water, the lower the freezing point. Very salty water freezes at around -21 °C, or about -6 °F.” (http://scienceline.ucsb.edu/getkey.php?key=3695, National Science Foundation,2013) This reveals that with the right ingredients the freezing point can be altered. During this process two substances are used, sugar and salt. They are very common and that’s why they will be most helpful to test because it is something everyone knows. But sometimes not everyone knows what’s actually happening behind the scenes. “The positive and negative areas of water molecules are attracted to the oppositely charged ions in salt and to the positive and negative areas on sugar molecules.” (http://www.inquiryinaction.org/chemistryreview/solids/,American Chemical Society,2017) This explains how water molecules can and will connect with different solutes. When this happens the water will change, meaning an almost domino effect will happen because this will cause the freezing point to change. Since the goal to be achieved is to answer the testable question, first, it needs to be broken down into the two categories that are being tested, sugar and salt. When using salt something strong to remember throughout the project is that it is made up of the elements Na and Cl which makes it NaCl. “During this phase change, water molecules enter and leave the solid at the same rate. Salt disrupts this equilibrium by simply being present. With the addition of salt, fewer water molecules are present at the interface between liquid and solid. In other words, salt particles block the water molecules from re-entering the solid phase, so more water molecules are leaving and less are entering the solid.” (http://blog.science-matters.org/2011/09/26/chemistry-the-effect-of-salt-on-the-freezing-point-of-water/,Eaton,2011) This shows how salt can really break down and tear away at an ice structure. So if it can do that how will it build up and ice structure? When salt is dissolved in the water they are now one, meaning whatever would happen to water still will it just is now intensified because of the other element added. In this experiment sea, salt/ table salt was being used therefore it may have different results to someone who may have used a different type of salt. “Most table salt also has added iodine, an essential nutrient that helps maintain a healthy thyroid. Sea salt and table salt have the same basic nutritional value, despite the fact that sea salt is often promoted as being healthier. Sea salt and table salt contain comparable amounts of sodium by weight.” (https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/sea-salt/faq-20058512, Zeratsky, 2016) This explains that the different types of salts may have an effect on the freezing point of water. But throughout this experiment sea salt was used continuously which will provide accurate results. Last but certainly not least is sugar, also known as sucrose. Although it has been stated before, when substances are added to water it changes it meaning that sugar is allowed to do this too. “Sugar lowers the freezing point of water. This is because if sugar molecules are added to water, the resultant solute isn’t water anymore. The sugar-water mixture has different freezing properties to pure water.” (https://sciencing.com/sugar-affect-freezing-point-water-7194604.html, O’Keeffe,2017) This shows that along with salt sugar can change the freezing point this connects to how water freezes in general because water can take a while to freeze but when a substance is added it is almost like a “pick me up” in the sense that it helps the water out by speeding up the process. Sugar is made up of lots of different elements, it is very complex especially in comparison to salt because sugar’s molecular weight is about 342 grams while salt is only 58. “sugar is sucrose, a molecule composed of 12 atoms of carbon, 22 atoms of hydrogen, and 11 atoms of oxygen (C12H22O11). Like all compounds made from these three elements, sugar is a carbohydrate. It’s found naturally in most plants, but especially in sugarcane and sugar beets” (https://www.exploratorium.edu/cooking/candy/sugar.html, Science Cooking). Sugar is a very formed substance meaning that when it is added to something else it houses the power to change it completely. So the question still remains how do sugar and salt affect the freezing point? Since these substances are so powerful individually they and change the freezing point a great deal because of the way the mix of pure water and the temperature it is being frozen at. Materials and ProcedureMaterialsMaterialsQuantityTest TubesTest Tube RackBeakers100 ml graduated cylinderThermometerStir rodsStyrofoam CupPermanent marker71611211Procedure1: Grab your 6 test tube and label one of the test tubes and one of the 250 mL beakers as “#1”.2: Use your scale weight 2.9 g of table or sea salt (NaCl) into the beaker.3: Then pour the sea salt from the beaker to the cylinder4: Stir with the stir stick until all of the crystals are dissolved5: Place the test tube in the Styrofoam cup with the ice and salt.6: Stir the test liquid in the test tube gently with a thermometer while keeping track of the temperature.7: Repeat this with 2 more salt solutions and 3 sugar solutions8: Don’t forget about your pure water controlControlled Variables: The temperature for the freezing process and Amount Of waterIndependent Variable: The things that are being added to the water and the amount being added Dependent Variables: The ice crystals that will form in the test tubesResultsSolutionGrams Of the substanceMolecular weight of substance (g)Amount of water (kg)Molality (mol/kg)Test liquid #1 (NaCl)2.958.4430.10.50Test liquid #2 (NaCl)5.858.4430.11Test liquid #3 (NaCl)11.758.4430.12Test liquid #4(Sucrose)17.1342.29650.10.50Test liquid #5(Sucrose)34.2342.29650.11Test liquid #6(Sucrose)68.5342.29650.12Test liquid #7(Control)N/AN/A0.1N/ASolutionSubstanceVan’t Hoff FactorMolalityKf for waterExpected Freezing PointDepression (°C)Test liquid #1 NaCl20.50-1.86-3.72Test liquid #2 NaCl21-1.86-3.72Test liquid #3 NaCl22-1.86-3.72Test liquid #4Sucrose10.50-1.86-1.86Test liquid #5Sucrose11-1.86-1.86Test liquid #6Sucrose12-1.86-1.86Test liquid #7WaterN/AN/A-1.86N/AConclusion, Reflection, and ApplicationConclusionMy science fair project was about testing how different solutes would affect the freezing time of pure water. I hypothesized that on average it would take about 15 minutes. I tested it by adding the mixture into a test tube and watching it freeze. My hypothesis was wrong because I thought it would take alot longer for each test liquid to freeze but on average with the solutes it was about 5 minutes instead of the 15 I originally predicted. I noticed that compared with the salt sugar did take a bit longer to freeze overall. But when I tested the salt and sugar against the same molality sugar froze a lot quicker than the salt did. This all proves that my hypothesis was incorrect because when I added up all the minutes and divided by the six solutes i tested the average was 5.1 minutes. I learned that salt and sugar have different effects on water and that everything is all connected through a large string of elements from the periodic table.ReflectionMy test was fair, although at times it would be hard to monitor what was going on all the time since the test tube was always halfway deep in the styrofoam cup. But other than that my results are pretty accurate because even without vision of the test tube all the time I still checked and made sure everything was correct. If I could change my experiment I would probably test more solutes, try and find a clear cup, maybe I would try it with different liquids and I would organize my data better. This experiment has opened new doors for me, I would like to test out melting points and what would happen if I were to use something like calcium chloride (CaCl2).Application This experiment can be very helpful because in the winter when it’s icy most people would like to know what they can do so it won’t be as slick. They will also want to know what will do it the fastest also. The results are helpful because a scientist could also be a manufacturer and it will be very useful for them to know what they can use to best serve and help people with their icy driveways. Ice is used in so many real life situations so knowing how to handle it will make things very easy on people in general. My experiment shows how the freezing point of water works because with the right solutes it can be tweaked.Reference ListEaton, Anna. “Chemistry: the Effect of Salt on the Freezing Point of Water.” Science Matters, 26 Sept. 2011, blog.science-matters.org/2011/09/26/chemistry-the-effect-of-salt-on-the-freezing-point-of-water/.L.D., Katherine Zeratsky R.D. “Sea Salt vs. Table Salt: What’s the Difference?” Mayo Clinic, Mayo Foundation for Medical Education and Research, 4 May 2016, www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/sea-salt/faq-20058512.Data Research Analysis . “How Does Salt Lower the Freezing Point of Water? – World Of Chemicals.” World of Chemicals â?? Online Chemical Directory,Chemistry Portal,Aricles,News, 2017, www.worldofchemicals.com/558/chemistry-articles/how-does-salt-lower-the-freezing-point-of-water.html.National Science Foundation. ” Which Freezes Faster, Water or Salt Water?” UCSB Scienceline, 26 Jan. 2013, scienceline.ucsb.edu/getkey.php?key=3695.American Chemical Society. “Chemistry Review: Physical Change in Solids.” Chemistry Review | Solids | Inquiry in Action, 2017, www.inquiryinaction.org/chemistryreview/solids/.Science Buddies. “Chemistry of Ice-Cream Making: Lowering the Freezing Point of Water.”Science Buddies, 16 Oct. 2017, www.sciencebuddies.org/science-fair-projects/project-ideas/FoodSci_p013/cooking-food-science/chemistry-of-ice-cream-making#background.O’Keeffe, Jillian. “Why Does Sugar Affect the Freezing Point of Water?” Sciencing, 24 Apr. 2017, sciencing.com/sugar-affect-freezing-point-water-7194604.html.Science Cooking. “Science of Candy: What Is Sugar? | Exploratorium.” Exploratorium: the Museum of Science, Art and Human Perception, www.exploratorium.edu/cooking/candy/sugar.html.