Experiment 2 Note_enthalpy of fusion for water

Document Sample
Experiment 2 Note_enthalpy of fusion for water Powered By Docstoc
					   IZMIR INSTITUTE OF TECHNOLOGY

     Department of Mechanical
           Engineering




   THERMODYNAMICS I
              ME 206



Enthalpy of Fusion For Water
       Experiment 2



           3rd May, 2011
            Energy Lab.
              Room Z35




           Spring 2011
   Res. Asst. V. Egemen Ağakay
1. Introduction
The enthalpy of a fluid is an important thermodynamic property that is inseparably
connected with the first law of thermodynamics for open systems. The enthalpy of fusion
for water is the energy removed from 0°C liquid water to make 0°C solid ice or vice-versa.
The purpose of the experiment is to determine the enthalpy of fusion for water.



2. Theory and Principles
In the experiment, hot water will be used to melt ice cubes at its melting temperature (0°C)
in a styrofoam cup calorimeter. The ice cubes will remain at 0°C until it is melted. As the ice
melts, hot water will loose heat to the ice and ice-water mixture occurs. The heat lost by
hot water and ultimately the enthalpy of fusion of ice can be calculated by measuring the
initial temperature of hot water and the final temperature of the mixture. The required
equation is derived from the 1st Law of Thermodynamics.



           Heat gained by ice + Heat gained by mixture = Heat lost by hot water



                      (m1)(hfus) + (m2)(Cp)(ΔT1)= - [(m3)(Cp)(ΔT2)]


Where;

m1 : mass of ice (kg)

hfus : enthalpy of fusion of water (kJ/kg)

m2 : mass of ice-water mixture (kg)

Cp : specific heat of water (= 4.18 kJ/kgK)

ΔT1 = (Tf -Tice): difference between final temperature of mixture and initial ice temperature
(°C)

m3 : mass of the hot water (kg)

ΔT2 = (Tf -Ti): temperature difference between final temperature of mixture and initial hot
water temperature (°C)
3. Experimental Set-up
You are expected to set-up your experiment using the procedure given in Section 4. The
materials that you will use for the experiment are listed below. All these materials will be
provided by Energ and Fluid Mechanics Lab. and Geothermal Energy Research Center.

      100-200 ml styrofoam coffee cup and lid,
      100 ml graduated cylinder,
      Thermometer,
      Electronic scale or triple beam balance,
      Ice cubes or chips,
      Pure water,
      Heater,
      400 ml beaker.



4. Procedure
    Styrofoam coffee cups will be used to obtain an insulated container in which ice and
     hot water will be mixed and phase change will occur.

          o Insert one cup into another as shown in figure below. The air in between two
            cups causes insulation.




    Having prepared the container, it is weighted by an electronic scale.

    Heat the water and measure its volume by a graduated cylinder or weight it.

    Put the hot water into the container and measure the hot water temperature.

    Add ice cubes or chips to the hot water and weight the whole system again.

    Insert the thermocouple into the ice-water mixture, cover the container by a lid and
     measure temperature until temperature change stops (steady-state).
    Record all the measurements.

    Repeat the experiment 3 times.



5. Results
    Present all recorded data in a table.

    Compute the enthalpy of fusion of water for each experiment and fill the table below
     (Exhibit the calculations for one experiment set).

                                                   1             2             3

  Mass of the container (mc)

  Mass of hot water+container (mw)

  Mass of hot water+container+ice (mi)

  Initial temperature of hot water (Ti)

  Final temperature of mixture (Tf)

  Initial temperature of ice (Tice)

  Enthalpy of fusion for water (Hfus)



    Visualization of the results with tables, graphics, photos, videos etc. is strongly
     advised. Define these visualization elements well.

    Indicate the steps of the experiment, Define the parameters that you measured and
     the way you obtained these parameters. Give your comments and conclusions.

    Write a report with YOUR OWN WORDS. PLEASE                 DO NOT COPY FROM
     ANYONE AND HANDOUT.



6. References
Show your references here in order of appearence in the text. Example:

[1] Aprea, C., R. Mastrullo, and C. Renno, “Fuzzy Control of the Compressor Speed in a
    Refrigeration Plant,” International Journal of Refrigeration 27 (2004): 639-648.

				
DOCUMENT INFO