Physical and Chemical Changes lab

 

Name: __________________________                                                         Hour: ______

 

Due Date :________________

 

Physical and Chemical Changes Lab

 

Objectives:

  1. To distinguish between a chemical and physical change.
  2. To become familiar with multiple types of laboratory procedures.

 

Equipment and Material:

           

Magnesium                                           Bunsen Burner

            Sodium Hydroxide                                Test Tubes (regular and large)

            Hydrochloric Acid                                Test Tube brush

Calcium                                                Watch Glass

            Ammonium Dichromate                        Splint

            Baking Soda                                         Tongs

            Vinegar

 

 

Procedure:

 

A.  MAGNESIUM- obtain a piece of magnesium from your instructor.  Using a pair of tongs, hold the magnesium into the flame of the Bunsen burner.  When the magnesium has been ignited, remove from the flame and allow it to finish burning.  CAUTION: Do not look directly at the magnesium as it is burning.  It will hurt your eyes!!  Let the magnesium cool then place in garbage can.

 

1.  Record 3 physical properties of Magnesium.

a.

b.

c.

 

2.  Record 2 observations during heating.

a.

b.

 

3.      Is this a chemical or physical change?

 

 

4.  If a chemical change occurred, what evidence indicated this?

 

 

 

 

B.  SODIUM HYDROXIDE- obtain 3-4 pellets of sodium hydroxide on a watch glass.  Set the watch glass and the sodium hydroxide aside for ten minutes.  Observe the pellets carefully after this time.  Place pellets in garbage can when finished.

 

1.  Record 3 physical properties of Sodium Hydroxide

a.

b.

c.

 

2.  Record 2 observations after sitting for ten minutes.

a.

b.

 

3.  Is this a chemical or physical change?

 

 

4.  If a chemical change occurred, what evidence indicated this?

 

 

 

 

 

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C.  HYDROCHLORIC ACID and CALCIUM- have a teacher help fill a large test tube ¼ full of hydrochloric acid.  Obtain a small piece of calcium from your instructor.  Carefully drop the piece of calcium into the hydrochloric acid.  After the reaction has begun, invert a clean test tube over the reacting tube.  After the gas has had a chance to collect in the upper test tube, test it with a lighted splint.  Pour the excess acid into the sink and dilute with cold water.

 

1.  Record 3 physical properties of calcium.

a.

b.

c.

 

2.  Record 2 observations after mixing.

a.

b.

 

3.  Is this a chemical or physical change?

 

 

4.  If a chemical change occurred, what evidence indicated this?


 

D.  ***DEMO***AMMONIUM DICHROMATE- place some solid ammonium dichromate in the bottom of a clean, dry, large test tube.  Fill the test tube to a depth of about ¼ inch.  Heat the bottom of the test tube gently.  CAUTION:  as you heat the test tube point it away from people.  When the ammonium dichromate begins to glow, remove it from the flame and observe what happens.  Let the products cool and then empty the remains into a wastebasket.

 

1.  Record 3 physical properties of ammonium dichromate.

a.

b.

c.

 

2.  Record 2 observations after heating.

a.

b.

 

3.  Is this a chemical or physical change?

 

 

 

4.  If a chemical change occurred, what evidence indicated this?

 

 

 

 

 

 

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E.  BAKING SODA and VINEGAR- place a small amount of sodium bicarbonate (baking soda) in an evaporating dish.  Carefully add a few drops of acetic acid (vinegar) a few drops at a time.  Wash mixture down drain.

 

1.  Record 2 observations after mixing.

a.

b.

 

2.  Is this a chemical or physical change?

 

 

3.  If a chemical change occurred, what evidence indicated this?

 

 

 

 

 

 

F.  SALT AND WATER-place a scoop of salt (NaCl) in 100 ml. of water (H20).  Stir using a stirring rod.  Wash mixture down drain.

 

1.      Record 2 observations of NaCl before mixing.

       a.

       b.

2.      List 2 observations of H20 before mixing.

a.

b.

3.      Record 2 observations after mixing.

a.

b.

4.      Is this a chemical or physical change?

 

 

5.      If a chemical change occurred, what evidence indicated this?

 

 

 

 

 

 

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