OXIDATION-REDUCTION REACTION OF MAGNESIUM

INTRODUCTION For this experiment we studied an oxidation-reduction reaction of magnesium and hydrochloric acid solution. We compared the experimental measured amount of a product and the amount predicted by the theoretical calculation of a balanced equation: Mg (s) + 2HCl (aq) → MgCl2 (aq) + H2 (g) PROCEDURE First we obtained a strip of pre-cut magnesium ribbon, cleaned it with steel wool to remove any signs of oxidation from the strip (which would alter our results), and then weighed it (individual masses of the magnesium strips for each trial can be found in Table I below). We filled a large beaker more than half way full with warm tap water. We allowed the water to sit for a while to bring it to room temperature. While the water equalized, we obtained a 100ml-graduated cylinder and filled it with tap water (also at room temperature), and created with a lid of plastic wrap. It was important when creating this lid that no air bubbles formed under the lid. Then we inverted the graduated cylinder in the beaker full of water and carefully removed the lid. We folded up our magnesium ribbon and wrapped it with a short piece of copper wire so the magnesium would react and not break off during the reaction. We put this magnesium piece at the bottom of the beaker underneath the graduated cylinder. Using a thistle tube we gently propped the end of the tube up under the inverted graduated cylinder and then poured 10ml HCl into it. As the magnesium began to react, we slowly pulled the tube out and waited as the gas bubbles began to displace the water in the cylinder. After all the magnesium was consumed, we moved the graduated cylinder up and down in the water to equalize the water levels. Once we had accomplished this we took a reading of the amount of gas collected in the cylinder. We repeated this two more times.

RESULTS TABLE I: GAS MEASUREMENT FOLLOWING REACTION TRIAL I TRIAL II TRIAL III Mg Strip Mass: 0.07g Mg Strip Mass: 0.07g Mg Strip Mass: 0.08g Volume of Gas 80ml