phase when the liquid boils, not the temperature of the air inside the test tube. Therefore, you will want the tip of th

[answerhappygod]

Phase When The Liquid Boils Not The Temperature Of The Air Inside The Test Tube Therefore You Will Want The Tip Of Th 1 (115.84 KiB) Viewed 117 times

phase when the liquid boils, not the temperature of the air inside the test tube. Therefore, you will want the tip of the thermometer to be within 1 - 2 in of the surface of the liquid inside the test tube - not touching, but fairly close. Watch the thermometer carefully as you heat the water. The temperature will rise until your sample starts to boil and then the vapor with start to condense on the bulb of the thermometer. You should recognize that boiling and condensing are opposite phase changes, but they happen at the same temperature. Once your sample is condensing on the bulb of the thermometer and dripping back into the solution, the temperature reading should stabilize at a steady state value. This means the thermometer is now reading at the boiling point of the liquid. Record the boiling point of your liquid.. Boiling Point: 71.2°C 3) Miscibility: This test determines which liquids will mix to form a single phase. You will test your sample liquid with each of the other samples and with distilled water. Take 4 small test tubes, making sure they are clean and completely dry. Add 1 mL of your liquid to each test tube. Now add 1 mL of de-ionized water to one test tube, and 1 mL of the other three liquid samples to each of the other test tubes. Cork the tubes and shake them vigorously to fully mix the liquids. Allow the test tubes to sit undisturbed for 2 minutes and then observe and record the results as miscible, immiscible, or partially miscible. Do the two liquids combine to give one layer (miscible, m), or do they remain in two layers (immiscible, i)? If there are two layers, are the layers equal in volume? If they are not, then you have a "partially miscible, p" mixture. This means some of the liquids mixed, but not all will mix. Report your results: Your sample liquid: n- hexane Miscibility: With (water)_______ Liquid 1( Collect Density Data for each liquid: n-hexane 2-Propanol Collect Boiling Point Data for each liquid: Ethyl Acetate Average: Liquid 2 ( Water 83.4 G-hexane 65.2°C 2-Propanol 81.5CEthyl Acetate 67.0°C 82,0°C 67.2°C 82.3°C 11.2°C
Analysis: List the experimentally determined boiling points from low to high: List the order (low to high) you would expect based on the molar mass data alone: How do intermolecular forces help to explain the boiling point trend in your data? Post Lab Exercise: IMFs, Phase Diagrams, and Energy Use the provided thermodynamic data to 1) sketch a phase diagram (see instructions below) and 2) place a line representing your heating at atmospheric pressure 3) calculate the energy input required to heat 100.00 g of your sample liquid a) from 25 °C (room temperature) to the boiling point. (use the average value for your boiling point). Pressure (atm) Temperature (°C) Instructions for sketching a phase diagram: 1) Place the triple point in the lower left hand quadrant of your graph 2) Drop a line straight down to the temperature axis and write in the temperature of the triple point (don't worry about the pressure - you can ignore this) 3) Connect the three equilibrium lines to the triple point: a) the solid/gas equlibrium line, b) the solid/liquid equilibrium line, and c) the liquid gas equilibrium line. You are just sketching based on other phase diagrams, no need to graph actual points
4) 3/4 of the way up the pressure axis draw in a 1 atm pressure mark 5) From the 1 atm pressure mark, move straight right until you encounter your solid/liquid equilibrium line. Put a point for the normal melting point. Drop a line straight down to the temperature axis from this point and write in the temperature 6) Continue straight right until you encounter your liquid/gas equilibrium line. Put a point there for the normal boiling point (you determined this in your experiment) 7) Drop a line straight down from your normal boiling point to the temperature access and write in the boiling point. Your diagram is sketched, please note it will not be to scale, but that is OK... we are just sketching the general shape. Thermodynamic data to use for your calculations: AH fusion J/mol Cliquid AH vapor J/g*C J/mol 197.66 Jimol K) 28.85 kJ/mol 156 (mol K 32 kJ/mol 13 kJ/mol 2.68 kJ/mol 5.28 kJ/mol 2.68 J(K) 44.0 kJ/mol 10.48 Kind 170 J/(mol K) 31.94 kJ/mol n-hexane cyclohexane 2-propanol ethyl acetate C solid J/g*C Cgas J/g*C 142.6 J/mol K) 105.3 J/(mol K) 1.54 J(K) 125.8 J/(mol K) 189.3 K (-83.9 °C). ? Pa Triple Point Energy required to heat from 25 C to boiling for 100.00 g water: 178.0 K (-95.1 "C). 1.23 Pa 279.48 K (6.33 °C), 6.388 kPa 184.9 K (-88.2 "C). ? Pa Calculation space: Energy required to heat from 25 C to boiling for 100.00 g of your liquid: Melting Point -94 °C 6.47 °C -89 °C -83.6 °C Now think about your liquid as a heat transfer fluid for use in a solar energy collector. A good heat transfer fluid would be able to store a high amount of energy without boiling. Would your liquid be a better or worse heat transfer fluid than water? Explain as part of your answer how the intermolecular forces that exist help determine how much energy a fluid can store before it boils.