Types of Reactions Lab
In this experiment you will cause several reactions to occur. From your tests, observations and powers of deduction, you will be able to (1) describe the products; (2) name the products: (3) identify the “type” of reaction: and (4) balance the chemical equation for the reaction.
Reaction 1: Place one heaping spoonful of potassium chlorate in a dry test tube. Clamp at a 45-degree angle to a ring stand. Heat with a Bunsen burner, slowly at first, until it melts and then starts to give off a colorless gas (looks like smoke). Light a wood splint, let it burn a few second, and then blow it out. Then quickly hold the glowing splint jus inside the mouth of the test tube. The splint busting into flame again verifies the presence of oxygen. There is a pinkish-white solid that remains in the test tube.
Reaction 2: Put 2 squirts of copper (II) sulfate solution in a test tube. Place a shine strip of zinc metal in the test tube and observe for several minutes. (Go on to another section and return.) Pour off the liquid into the sink, but dump the solids on a paper towel. Remove the leftover zinc (save for Reaction 6) and inspect the precipitate, which is a finely divided powder. Another product remains dissolved in the solution.
Reaction 3: Obtain a 2-cm length of magnesium ribbon. Holding one end with the crucible tongs, ignite the other end in a Bunsen burner flame. WEAR GOGGLESAND DO NOT LOOK DIRECTLY A THE FLAME! Hold the magnesium over the base of the ring stand as it burns. With what in the air is the magnesium reacting? Describe the product.
Reaction 4: To a test tube, add one squirt of a solution of potassium chromate and one squirt of a solution of barium chloride. Swirl to mix. Describe the precipitate that forms.
Reaction 5: place one large spoonful of sodium bicarbonate in a dry metal crucible. Place in a triangle on a ring on a ring stand; partly cover with a watch glass, leaving enough space open at one edge to insert a wood splint. Heat with a Bunsen burner, slowly at first, until it starts to give off a colorless gas. Light a wood splint, let it burn a few second, DO NOT BLOW OUT. Insert the lit end into the crucible. The flame being extinguished verifies the presence of carbon dioxide. Observe any deposit on the watch glass. There is a white solid that remains in the crucible.
Reaction 6: Put the zinc strip from Reaction 2 back in a test tube and add 2 squirts of dilute hydrochloric acid (HCl). Cover the test tube with your thumb for one or two minutes until you feel some pressure. Light a match and hold it (still lit) over the mouth of the test tube to test for flammability, which indicates hydrogen gas. This test may be repeated as long as gas is being produced. Pour the unused acid down the sink. Save and leftover zinc and throw away in the wastebasket.