Method/Equipment

Equipment: 50g NaCl Distilled water Sensitive weight scales Dissolved Oxygen probe Test tube rack Test tubes 20cm Magnesium 20g Zinc Method: 1) Obtain test tube rack containing three separate test tubes. Add 20mL distilled water to each test tube, before placing 1, 3 and 7g of NaCl in each and swirling to dissolve. Measure Dissolved oxygen content. 2) Scour oxide off 3 x 1cm long strips of magnesium. Record weight and calculate density and area of metal. Place each strip into one each of the three test tubes, and leave for one day. 3) Repeat above two steps with Zinc, and considering the metal is in crystal format, use exact weight of the magnesium strips in each test tube. 4) Repeat previous tests for both Zinc and Magnesium, though before doing so ensure water is aerated. Add required amounts of salt before testing dissolved oxygen levels.