Observations of Chemical Change and Physical Change
July 7, 2015
Purpose: To perform a variety of chemical reactions and make scientific observations to describe the chemical change.
Equipment: Pie pan, dish soap, distilled water, matches or lighter, pair of sunglasses, paper towel, scissors, sheet of black paper, sheet of white paper, source of tap water, sunlight (needed for 30 minutes); burner fuel, 2 pairs of gloves, pipet, empty short-stem pipet, goggles, spatula (metal), test tube clamp holder, 4 test tubes, test tube rack, tweezers, 2 well-plates, 1 Experiment Bag: Observations of Chemical and Physical Changes.
Exercise 1 Procedure:
First, set a sheet of black ...view middle of the document...
Dry with paper towels and wash hands thoroughly. Squeeze out any remaining chemicals from pipets into drain and rinse with ample amounts of tap water and throw away. Place all equipment back in box for future use.
Exercise 2 Procedure:
First, put on safety goggles and gloves. Gather magnesium metal, copper carbonate (CuCO3), copper nitrate (Cu(NO3)2), and mossy zinc. Observe each of the chemicals physical properties (color and state of matter) and record in Data Table 2 under “Initial Observations.”
Then, place the four test tubes into empty wells of test tube rack. Use tweezers to put 1 piece of magnesium into a test tube and 1 piece of mossy zinc in another.
Use spatula to add a pea-sized amount of CuCO3 into a test tube and a pea-sized amount of Cu(NO3)2 into another test tube.
Place burner fuel on pie plate and uncap the fuel, then light the wick. Use test tube clamp holder to pick up test tube w/ magnesium metal and hold it over flame to heat metal in tube. HOLD TEST TUBE SO OPENING OF TEST TUBE FACES AWAY FROM YOURSELF AND OTHERS. Observe the effects of heating magnesium in test tube and record observations in Data Table 2.
Repeat steps 9 and 10 for three remaining chemicals listed in Data Table 2.
READ REST OF THE STEPS BEFORE MOVING ON.
Using the spatula (for powders) or tweezers (for metal pieces), hold a chemical in the flame. Hold tweezers and/or spatula at their farthest points, away from the flame. Keep all loose clothing and hair away from flame and substances, and keep flame away from face.
a. For powder: Only use a small amount (half the size of a pea) of the chemical on the end of spatula. Leave spatula in flame until all powder has reacted.
b. For metal pieces: Only use 1 piece of metal each, squeezing ea. w/tweezers at very end of tweezers. When burning mag., wear sunglasses under goggles to protect eyes. Ensure that each piece of metal is kept over al. foil or pie plate.
Wash spatula and tweezers after each use, and remember that they will be very hot after putting them in flame. Make sure that they’ve cooled before touching with gloved hand.
Record observations for burning each chemical in Data Table 2.
Extinguish flame from burner by carefully placing cap on top of flame. When burner has cooled, clean all equipment and return to box for future use.
Results in Data Table 1: A1 (NaHCO3 and HCl) – Became fizzy and bubbly, produced a chemical change; A2 (NaOCl and KI) – Observation 1: Turned brown, Observation 2: Became black...