The purpose of this lab was to differentiate between accuracy and precision by calculating the mass per millimeter, or the density of the unknown liquid using two different methods

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                Etran Bouchouar

                5/10/2007

Does Accuracy and Precision Play a Role in Calculating the Density of an Unknown Liquid by Two Different Methods?

Purpose:

The purpose of this lab was to differentiate between accuracy and precision by calculating the mass per millimeter, or the density of the unknown liquid using two different methods. The test is done three times to measure precision (how exact a measurement it) and to measure accuracy (how close a value is to the accepted value).

Hypothesis:

I believe that method 1 will be precise in density, volume and mass, and that method number 2 will be accurate in those related fields.

Materials:

  • 100mL beakers (3)              
  • 100mL graduated cylinder
  • Thermometer
  • Felt tip pen
  • Ruler
  • Electronic balance

Procedure:

  1. Prepare a data table. Include room in your table for three trials for each method.
  2. Using a felt tip pen, make a mark on one of the 100mL beakers about 2 cm from the top. Measure the height inside the beaker from the mark to the bottom of the beaker. Measure the inside radius of the beaker.
  3. Measure the mass of the empty beaker.
  4. Carefully fill the beaker to the mark with the unknown liquid. Measure the mass of the beaker and the liquid.
  5. Measure the temperature of the liquid.
  6. Pour the liquid into a 100mL graduated cylinder. Carefully measure the volume of the liquid. Be sure the top of the liquid is exactly at eye level when the measurement is taken.
  7. Repeat steps 2 through 5 with a second and third beaker.

Observations:               Dimensions & Mass of Beaker, Mass of Liquid, and Volume of Liquid

                      in Graduated Cylinder.

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Analysis:

  1. Density = Mass                Density = Mass                Density = Mass

                       Volume                                   Volume                                   Volume

      Density =  69.87                      Density = 68.15                Density = 71.51  

                      Pie(2.25)( 4.9)                       ...

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