When you pour a solution of hydrogen peroxide, H₂O₂, over a cut, an enzyme in your blood decomposes it to produce oxygen gas, O₂, as evidenced by the bubbling that takes place. It is this oxygen at high concentrations at the site of the injury that kills off microorganisms. A similar enzyme is found in baker’s yeast. Wear safety glasses and remove all combustibles, such as paper towels, from a clear countertop area. Pour a small packet of baker’s yeast into a tall glass. Add a couple capfuls of 3% hydrogen peroxide and watch oxygen bubbles form. Test for the presence of oxygen by holding a lighted match with a tweezers and putting the flame near the bubbles. Look for the flame to glow more brightly as the escaping oxygen passes over it. Describe oxygen’s physical and chemical properties.