Charles law Lab by 74l0Y9

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									Name: ________________________________                   Date: _______________

Lab Partner(s): ____________________________________________________

                               Charles’ Law Lab

Purpose:
   To explore the relationship between volume and temperature at constant
     pressure. Charles’ Law.
   Graph Volume VS Temperature data, determine the shape of the graph and
     determine the relationship between pressure and volume from the graph.

Materials: hot plate; 400ml beaker; 250ml beaker; thermometer; syringe with cap;
           ice; ceramic/wire square; beaker tongs

Procedure:

   1. Using a hot plate, heat 250ml of water in a 400ml beaker to ~70ºC.
   2. While the water is heating ½ fill the 250ml beaker with ice and prepare the
      syringe. Remove the cap and draw 20cc of air into the syringe then place the cap
      on the syringe nozzle.
   3. When the water reaches 70ºC, carefully remove the water from the hot plate
      using beaker tongs and place the hot beaker on the ceramic square located on the
      lab bench. Unplug the hot plate.
   4. Place the thermometer in the hot water.
   5. Hold the syringe by its top and push the portion of the syringe containing the
      trapped air under the hot water. Wait a few minutes for the air in the cylinder to
      equilibrate, then measure the temperature of the water and the volume shown on
      the syringe scale. When measuring the volume of the trapped air it is helpful
      to quickly push the piston down into the cylinder then release it. This will
      help overcome the effects of friction between the piston and cylinder walls.
      Record the volume. Measure the volume again, but this time give the piston
      a sharp pull outward and release it. The measured volume in this case will
      be larger. Again this is due to friction between the piston and cylinder wall.
      The actual volume will be the average of these two measurements.
   6. Allow the water to cool by 10ºC you can add a small amount of tap water to help.
      Record this temperature and make a new volume measurement following the
      procedures in step 5.
   7. Repeat this procedure of cooling by 10ºC and measuring the temperature and
      corresponding volume until you reach 0ºC. From 30ºC and lower it may be
      necessary to add small pieces of ice to help bring the temperature down.
   8. Using EXCEL enter the collected data for temperature and volume. In Column
      A, type Temperature in ºC, underneath put all the temperatures. In column B,
      type average (actual) volume in cc, underneath put all the volumes.

   9. Graph the data using Excel. Click on the multicolor bars on the top task
      bar, this is the graphing key. Select x;y scatter graph and choose the smooth
      curve graph. Now follow the directions on the screen. Make sure you
      include your names in the title of the graph.


Questions and Conclusions:

   1. Look at the graph of data. Describe what happens to the volume of air in the
      syringe as you decrease the temperature.




   2. Describe the shape of the graph.




3. How would you describe the relationship between temperature and volume?

								
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