Results, error calculations and corrosion rate

Table 1- Corrosion Rate of Magnesium in stagnant solution Test Tube Number Amount of NaCl in Tube (g) Weight of Magnesium strip (g) weights used to estimate weight loss Dissolved Oxygen content (mg/L) Density (cm3) Volume (cm3) Corrosion Rate (mmpy) 1 1.0 Original: 0.010 Test 1: 0.015 Test 2: 0.008 7.4 3.3 0.003 12.3 2 0.5 Original: 0.033 Test 1: 0.017 Test 2: 0.007 6.8 11.0 0.003 8.3 3 0.3 Original: 0.016 Test 1: 0.013 Test 2: 0.007 6.6 5.3 0.003 5.7 Table 2- Corrosion Rate of Magnesium in aerated solution Test Tube Number Amount of NaCl in Tube (g) Weight of Magnesium strip (g) weights used to estimate weight loss Dissolved Oxygen content (mg/L) Density (cm3) Volume (cm3) Corrosion Rate (mmpy) 1 1.0 Original: 0.007 Test 1: 0.003 Test 2: nil 7.9 2.3 0.003 52.9 2 0.5 Original: 0.012 Test 1: 0.005 Test 2: nil 6.5 4.0 0.003 30.4 3 0.3 Original: 0.012 Test 1: 0.005 Test 2: nil 7.8 4.0 0.003 30.4 Table 3- Corrosion Rate of Zinc in stagnant solution Test Tube Number Amount of NaCl in Tube (g) Weight of Zinc strip (g) weights used to estimate weight loss Dissolved Oxygen content (mg/L) Density (cm3) Volume (cm3) Corrosion Rate (mmpy) 1 1.0 Original: 0.221 Test 1: 0.220 Test 2: 0.218 6.1 12.3 0.018 2.0 2 0.5 Original: 0.190 Test 1: 0.191 Test 2: 0.189 6.0 10.6 0.018 2.3 3 0.3 Original: 0.211 Test 1: 0.211 Test 2: 0.210 5.9 11.7 0.018 2.1 Table 4- Corrosion Rate of Zinc in aerated solution Test Tube Number Amount of NaCl in Tube (g) Weight of Zinc strip (g) weights used to estimate weight loss Dissolved Oxygen content (mg/L) Density (cm3) Volume (cm3) Corrosion Rate (mmpy) 1 1.0 Original: 0.284 Test 1: 0.282 Test 2: 0.281 9.6 15.8 0.018 7.7 2 0.5 Original: 0.258 Test 1: 0.258 Test 2: 0.256 9.5 14.3 0.018 4.3 3 0.3 Original: 0.280 Test 1: 0.281 Test 2: 0.280 7.8 15.6 0.018 *Not enough change to even make an estimate as to the amount of corrosion Calculations: Error and Uncertainty- Table 1: % uncertainty for weight of magnesium strip (test 1): % uncertainty= 0.05/0.01 × 100=500% % uncertainty for weight of magnesium strip (test 2): % uncertainty= 0.05/0.033 × 100=151.5% % uncertainty for weight of magnesium strip (test 3): % uncertainty= 0.05/0.016 × 100=312.5% Table 2: % uncertainty for weight of magnesium strip (aerated-test 1): % uncertainty= 0.05/0.007 × 100=714.3% % uncertainty for weight of magnesium strip (aerated-test 2): % uncertainty= 0.05/0.012 × 100=416.7% % uncertainty for weight of magnesium strip (aerated-test 3): % uncertainty= 0.05/0.012 × 100=416.7% Table 3: % uncertainty for weight of zinc strip (test 1): % uncertainty= 0.05/0.221 × 100=22.6% % uncertainty for weight of zinc strip (test 2): % uncertainty= 0.05/0.190 × 100=26.3% % uncertainty for weight of zinc strip (test 3): % uncertainty= 0.05/0.211 × 100=23.7% Table 4: % uncertainty for weight of zinc strip (aerated)(test 1): % uncertainty= 0.05/0.284 × 100=17.6% % uncertainty for weight of zinc strip (aerated)(test 2): % uncertainty= 0.05/0.258 × 100=19.4% % uncertainty for weight of zinc strip (aerated)(test 3): % uncertainty= 0.05/0.280 × 100=17.8% Corrosion Rate: All corrosion rates were calculated based on the formula; mmpy=87.6 × W/DAT where W=weight loss in grams; A= area of metal;D=metal density; T=time exposed