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Misael Barradas Balderrama September 9th, 2020 Phase Diagram t-Butylalcohol(Notebook) Procedure: What is a phase diagram? Is a type of chart used to show conditions at which thermodynamically distinct phases occur and coexist at equilibrium. What is a triple point? The triple point of a substance is the temperature and pressure at which the three phases of that substance coexist equilibrium. What is the technical definition of boiling point and how would you know when to stop heating during boiling point determination? Boiling point is when the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid and the liquid changes into a vapor. And I would know it is at boiling point when bubbles are vigorously emerging from the beaker What makes the triple point to be arrived at when the apparatus is attached to an aspirator which generates the vacuum or a vacuum pump? The triple point occurs where the solid, liquid, and gas transition curves meet The objective of this experiment is to determine the boiling, freezing, and triple point of t-butyl alcohol. The boiling point of the substance will be found by using a boiling water bath, a thermometer, and t-butyl alcohol. The freezing point will be found by using ice water to determine at what temperature it freezes. And last, the triple point will be found by reducing the pressure in a closed flask until the triple point can be seen, then temperature will be recorded as well.

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Phase Diagram t-Butylalcohol

By Misael Barradas Balderrama

Report submitted to Chemistry Faculty September 23rd, 2020

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Introduction Substances have different boiling, freezing, and triple point temperatures. This is due to their different intermolecular forces, molecular weight of the compound, and physical state(solid, liquid, or gas). Boiling points can be identified by looking at the substance until bubbles start forming vigorously. Freezing point will be known when the substance solidifies(freezes). The triple point is where equilibrium between solid, liquid, ang gas is found. To reach the triple point, pressure will have to be lowered because it requires a lower pressure of t-butyl alcohol for this reaction to take place. When triple point happens boiling and freezing can be seen at the same time. In this experiment boiling, freezing, and triple point of t-butyl alcohol will be observed.

Safety and Hazard information Goggles were worn to prevent any foregin fluids from getting in contact with the eyes. Lab aprons were worn to prevent clothes getting burnt from the chemicals. Using a fume was needed to prevent vapor inhalation. Reading the experiment before lab class to have an idea of what the experiment was going to be like helped to organize and handle material properly. Using a water bath to keep flames away from getting in contact with the highly flammable substance. Cleaning and disinfecting the lab glassware and table before and after use to prevent contamination.

Materials and Methods The chemicals used in this experiment were water, t-Butylalcohol, and glycerine. Materials used were 600 mL beaker, 400mL beaker, large test tube, rubber stopper, tubing with glass insert, thermometer, ring stand, and boiling stones.

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1. Triple point procedure: A rubber stopper with two holes with no split, thermometer, a large test tube, and a rubber tubing was obtained. The bulb of the thermometer was lubricated along with one hole of the rubber stopper with glycerine to facilitate smooth entering in the rubber stopper. Then the thermometer was slid into the rubber stopper hole. Next, the thermometer was placed all the way to the bottom of the test tube. Another rubber stopper, 250mL flask, a pan with ice water, and a short rubber tubing with glass insert was obtained. Three boiling stones were placed in the test tube along with t-butyl alcohol enough to cover the tip of the thermometer. Then the test tube was clamped into a ring stand. The water aspirator was turnt on before closing off the tubing connected to the trap, with a finger suction was tested. After closing the trap, the temperature dropped quickly. After a few seconds the liquid boiled and after a while boiling and freezing happened at the same time. The temperature recorded was 19.9 ° C.  Last, after recording the data the stopcock was opened to stop the suction and the water aspirator was turned off. The rubber stopper and thermometer were removed and the t-butyl alcohol was saved for the next experiment. 2. Boiling point procedure: A water bath with a 600mL beaker was prepared for the t-butyl alcohol to be heated (this is because t-butyl alcohol is flammable). Then, a test tube was filled with the t-butyl alcohol and clamped to a ring stand. Then, a thermometer was placed into a rubber stopper with a split 1 cm away from the substance to record the temperature when it boils. Last, the test tube with the  The test alcohol was placed in the boiling water bath and the boiling point recorded was 84.5 ° C. tube was removed from the water bath and the t-butyl alcohol was saved for the next experiment. 3. Freezing point procedure:

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First the test tube and t-butyl alcohol was cooled off. Then, Using the same set up a long stirrer was added to the test tube in the other hole in the rubber stopper. Then, the thermometer was submerged in the substance. Another 400mL beaker, but with ice water this time, was prepared. The ice water temperature was set to 18 °C.  Last, the test tube was submerged in the ice water and the temperature was taken every 15 second until freezing point. The freezing point recorded  Ater the experiments, the alcohol was dumped in the chemicals liquid waste and all was 13.5 °C. the equipment was cleaned and all put back.

Results and Discussion Boiling point temperature: 84.5 ° C  Freezing point temperature: 13.5 ° C  Triple point temperature: 19.9 ° C  Pressure: 29.96 in convert to → mm Hg convert to → atm= 1.00atm

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From the data recorded, the experimental boiling point was 84.5 C. The theoretical boiling point of t-butyl alcohol is 82.4 C. The difference in theoretical temperature and the experimental

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temperature might have come from a faulty thermometer or from not being careful while recording the data. These errors could have been avoided by handling the thermometer carefully and properly and taking the reading carefully.  The theoretical freezing point of t-butyl alcohol is The experimental freezing point was 13.5 °C. 25 ° C. The difference in data recorded might have come from using colder water temperature that was in the beaker and that could have caused the temperature to keep dropping after the freezing point was reached. This error could have been avoided by observing the t-butyl alcohol carefully until it became solid to record a more accurate result. The triple point was 19.9 ° C.  When the triple point happens, all three states of matter are the same, as it was seen in the experiment. From the triple point, any state change can happen without a drastic phase transition.

Conclusion The experiment was a success. Even though the temperatures were not 100% accurate, the values were close. Also, the triple point reaction was seen and this helped to understand the phase diagrams better and the process of the state changes.

References National Library of Medicine. (2005, march 26). Tert-Butanol  Retrieved from https://pubchem.ncbi.nlm.nih.gov/compound/tert-butanol...