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Properties of Matter: Investigation 2 –

Lab

 

 

 

 

 

 

 

MINDSET

This Investigation is designed to:

  • teach you how to calculate the density of an object,
  • help you explore the chemical properties of the samples that are the same color but have different physical forms,
  • promote discovery of the concept that although a compound may have different physical forms, its chemical properties are the same for each form, and
  • introduce you to the Determination of Density procedure.

BE PREPARED

Student Preparation for the Investigation includes gathering the following materials.

Note: The materials are listed in your SDR. They are also listed below for your reference.

  • (1) triple beam balance
  • (13) weigh dishes
  • (1) 1000 ml graduated cylinder
  • (1) marker
  • (8) 2cm pieces of masking tape
  • (1) pair of gloves for each student
  • (1) 250 ml graduated cylinder
  • (1) liter pitcher filled with 500 ml of water
  • (1) sample of unknown A through F
  • (1) centrifuge tube filled with 0.2M iron chloride solution
  • (1) centrifuge tube filled with 0.2M silver nitrate solution
  • (1) centrifuge tube filled with vinegar
  • (8) test tubes
  • (1) lab scoop
  • (1) test tube rack
  • (1) pair of forceps
  • (1) pair of goggles for each student
  • (1) glass stir rod
  • (1) stopwatch
  • (3) plastic pipette

INVESTIGATE

  • Review how to calculate density using the Calculation of Density procedure.
  • Reflect on the PreLab video as you move through the procedural steps.
  • During the Experiment, every procedural step is important. If one step is skipped, data can become invalid. To help you keep on track, read each step thoroughly, complete the step, then check it off (Read it – Do it – Check it off).
  • Complete each procedural step in your SDR.
Note: The procedural steps are listed below for your reference.
  1. Calculate the density for each of the unknown substances.
    1. Transfer the mass and volume of each unknown substance from Investigation One onto Table A.
    2. Use the space below for your calculations. Remember, the formula for calculating density is: Density = mass ÷ volume
    3. Record the density of each substance in Table A.
  • Discuss the prediction questions within your group and with your class. Next, you may want to continue your investigation by exploring some chemical properties of samples that have the same color but different physical forms.
  1. Test your prediction.

A. Locate Table B. The second column describes which compound will be added to each unknown. The third column describes how to test each unknown substance.

B. Test and Observe each combination for an initial reaction. Follow the procedure for each sample on Table B. Use the stopwatch to begin timing your reaction for 10 minutes.

C. Record: Write your initial observations in Table B in the Observation 1 column.

D. Record: After 10 minutes has passed, determine whether a chemical reaction occurred (bubbles or color change). Write your answers in Table B in the Observation 2 column.

CLEAN UP

Help your group return materials and clean the lab bench after you are finished with the experiment.