Chemistry – Metals - Corrosion of metals | e-Consult
Metals - Corrosion of metals (1 questions)
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Here's an experimental procedure to investigate the effectiveness of barrier methods in preventing rusting:
Materials Required:
- Iron nails (same size and type)
- Distilled water
- Salt (sodium chloride)
- Different barrier materials: paint, grease, zinc coating (galvanised nails), plastic coating
- Beakers or containers (same size and type)
- Scalpel or knife
- Balance
- Measuring cylinder
- Thermometer
- Stopwatch
Experimental Procedure:
- Preparation: Clean the iron nails thoroughly with sandpaper to remove any existing oxide layer. Weigh each nail and record the mass.
- Treatment: Apply each barrier method to several nails (e.g., 5 nails per method). Ensure the barrier is applied evenly. Allow the barrier to dry completely.
- Exposure: Place each treated nail in a beaker containing a solution of distilled water and salt (to accelerate rusting). Maintain a constant temperature (e.g., 20-25°C) using a water bath if necessary.
- Time: Leave the nails in the solution for a set period (e.g., 2 weeks).
- Monitoring Rusting: At regular intervals (e.g., every 2 days), remove a nail from each beaker. Carefully scrape off any rust using a scalpel or knife.
- Mass Measurement: Weigh the nails after scraping off the rust and record the mass. Ensure the scraping is consistent across all nails.
Measuring the Rate of Rusting: The rate of rusting can be determined by measuring the mass of rust formed over time. The difference between the initial mass of the nail and the mass after rusting represents the mass of rust formed.
Analysis of Results:
- Calculate the mass of rust formed for each nail at each time interval.
- Plot a graph of mass of rust formed against time for each barrier method.
- Compare the rates of rusting for each method. The method that results in the least amount of rust formation over time is the most effective.
- Consider the limitations of the experiment, such as variations in the application of the barrier and the potential for other factors to influence the rate of rusting.
By comparing the results, the student can determine which barrier method is most effective at preventing rusting under the specified conditions. The results should be presented clearly using graphs and tables to support the conclusions.