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What is the corrosion rate of a copper metal in a saline environment containing 0.5 M of NaCl solution, if the mass of the copper electrode decreases by 0.5 grams after 24 hours of exposure to the solution at room temperature (25 °C)?

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To calculate the corrosion rate of the copper metal, we need to determine the mass loss per unit area per unit time. First, let's convert the mass loss to moles and then to the area of the copper electrode.1. Convert mass loss to moles:The molar mass of copper  Cu  is 63.55 g/mol.0.5 g Cu *  1 mol Cu / 63.55 g Cu  = 0.00787 mol Cu2. Determine the number of electrons involved in the corrosion reaction:The corrosion reaction for copper in a saline environment can be represented as:Cu  Cu + 2eSo, for each mole of Cu, 2 moles of electrons are involved.3. Calculate the total charge passed during the corrosion process:1 mol of electrons has a charge of 96,485 C  Faraday's constant .Total charge = 0.00787 mol Cu * 2 mol e/mol Cu * 96,485 C/mol e = 1,517,000 C4. Calculate the current:Time = 24 hours = 86,400 secondsCurrent  I  = Total charge / Time = 1,517,000 C / 86,400 s = 17.55 A5. Calculate the corrosion rate:Corrosion rate is usually expressed in terms of mass loss per unit area per unit time  e.g., mm/year or mils/year . To calculate this, we need to know the surface area of the copper electrode and convert the mass loss to a length unit.Assuming a uniform corrosion rate and a cylindrical electrode, we can use the following formula to calculate the corrosion rate:Corrosion rate  mm/year  =  Mass loss  g  * Equivalent weight  g/equivalent  * 3.1536 * 10^7 s/year  /  Area  cm  * Time  s  * Density  g/cm  The equivalent weight of copper  Cu  is 31.77 g/equivalent  63.55 g/mol  2 equivalents/mol . The density of copper is 8.96 g/cm. We still need the surface area of the electrode to complete the calculation.Once you have the surface area of the electrode, you can plug in the values and calculate the corrosion rate in mm/year or convert it to mils/year  1 mil = 0.0254 mm .

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