Observing Chemical Reactions (Can Be Used For Assessment Layout Or For Actual Prac)
Writing Practical Reports
Aim:
To observe what happens during and after a chemical reaction.
Equipment:
Concentrated nitric acid in a glass dropping bottle
Small pieces of Copper
250ml Beaker
2 M Lead nitrate in a dropping bottle
2 M Potassium iodide in a dropping bottle
2 M Copper sulfate in a dropping bottle
2 M Sodium hydroxide in a dropping bottle
2 M Hydrochloric acid in a dropping bottle
4 Pyrex test tubes
Test tube rack
Spatula
Bunsen burner, gauze mat
Sandpaper
Magnesium Ribbon
Tongs
Safety glasses
Procedure:
1. This is a teacher-only demonstration.
Place a 250ml Beaker in the fume cupboard. Place the pieces of Copper into the Beaker and add 150ml of concentrated nitric acid to the beaker.
2. Add Potassium iodide to a test tube to the level of about 1cm. Add approximately the same amount of Lead nitrate to the test tube.
3. Add a small amount of Copper carbonate powder in a test tube. Strongly heat the test tube in the Bunsen burner.
4. Clean some Magnesium ribbon with sandpaper and place it in a test tube that is about one-third full with Copper sulfate.
5. Add a small amount of Hydrochloric acid to some sodium Hydroxide in a test tube. Feel the base of the test tube during the reaction.
6. Hold a piece of Magnesium ribbon in a pair of tongs and ignite the Magnesium by holding it in a Bunsen burner flame: Caution: Do NOT look at burning Magnesium directly look at it from off to the side.
Results:
Reactants Changes observed
Concentrated nitric acid and copper Froff, bubbles, brown smoke, original transparent liquid went green
Potassium iodide and lead nitrate Went a yellow, paint resembling liquid
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