Hobbies And Interests
Nitrogen Heat of Vaporization Experiment
Nitrogen, one of the major components of air, can be stored in liquid form. The liquid form of nitrogen is used to experiment with vaporization. The purpose is to determine the amount of heat energy needed to vaporize, or boil, liquid nitrogen. The heat energy in this experiment is called heat of vaporization. Heat 100 ml of water to 65 degrees C and add the water to a Styrofoam cup that you have weighed. Add 80 ml of liquid nitrogen to another Styrofoam cup that you have weighed and calculate the nitrogen mass or weight. Place the cup and nitrogen on a balance until 60 grams of nitrogen remain. Measure and record the temperature of the water in the cup. Add the liquid nitrogen to the water. Observe as boiling stops and fog resides. Record the final temperature and final mass of the cup and water. Use the results of the temperatures and mass to calculate the amount of energy required to vaporize one gram of liquid nitrogen.
The Isoteniscope Experiment
Measure the heat of vaporization of a pure liquid using the isoteniscope method. The isoteniscope is a device that uses a U-tube that has one end open and a side arm test tube. The samples are placed into the closed-end part of the U-tube and in part of the test tube to determine the vapor pressure. In this experiment the equilibrium vapor pressure of a pure liquid, as a function of temperature, and the heat of vaporization are determined. Assemble the isoteniscope and place the pure liquid sample into three quarters of the closed end in the U-tube of the apparatus. Place the sample in the side-arm test tube to cover three quarters of the U-tube. Place the U-tube into the test tube. Place the isoteniscope into a water bath at room temperature. Reduce the pressure within the isoteniscope by closing the needle valve and placing the stopcock to position 1. Record the initial temperature and pressure. Increase the heat of the water bath 4 degrees C. Record the temperature and pressure. Increase the heat of the water bath in increments up to 70 degrees C. Record the temperature and pressure at the selected increments. Create a graph to plot the temperature versus pressure.
Ethanol Heat of Vaporization Experiment
Conduct an experiment to determine the standard heat of vaporization for ethanol. Connect a glass bulb to a manometer. The manometer is a pressure reading device. Remove any gas from inside the bulb using a vacuum pump. Add liquid ethanol to the bulb. The manometer will create a closed system containing both liquid ethanol and ethanol gas. Read the manometer to record the initial temperature and pressure and at different times during vaporization. Complete vaporization of ethanol will occur when there is no more cloudy gas present. Create a chart or graph to illustrate the different temperatures and pressures during the phase of ethanol from liquid to gas.
Distilled Water Heat of Vaporization Experiment
Perform a heat of vaporization experiment with distilled water using a round bottom boiling flask, distillation condenser, burner, vacuum gauge, open mercury manometer, aspirator, needle valve and thermometer. Set the water flow to the aspirator to the highest vacuum as soon as the flow of water through the condenser is turned on. As the temperature of the distilled water increases and reaches the boiling point, the vapor pressure of the distilled water is equal to the external pressure. The vapor pressure results are obtained from the manometer reading. Record results. Increase the pressure within the vessel by opening the needle valve on the burner base. Measure and record the new boiling temperature and pressure. Observe how with increased pressure, the boiling stops. Plot the temperature versus pressure results on a graph to present with the experiment.