Describe how you would determine the melting point of a salt of benzoic acid with melting point of 170°c
To determine the melting point of a salt of benzoic acid with a melting point of 170°C, you would need to follow these steps:
1. Prepare a sample: Start by obtaining a small amount of the salt of benzoic acid. It is important to use a clean and dry sample, as any impurities can affect the accuracy of the measurement.
2. Set up the apparatus: You will need a melting point apparatus, which consists of a heating element and a capillary tube. Fill the capillary tube with the salt sample, making sure that it is tightly packed to ensure accurate results.
3. Calibrate the apparatus: Before starting the measurement, it is crucial to calibrate the apparatus by running a known reference substance with a known melting point. This helps ensure the accuracy and reliability of the apparatus.
4. Measure the melting range: Insert the capillary tube into the melting point apparatus and begin heating at a slow and steady rate. Observe the sample as it heats up and note the temperature at which the first drop of molten salt appears, known as the initial melting point. Continue heating until the entire sample has melted and note the temperature at which the complete liquefaction is achieved, known as the final melting point.
5. Determine the melting point: Typically, the melting point of a substance is reported as a range instead of a single temperature. The range is established by averaging the initial and final melting points. In this case, if the initial point is 168°C and the final point is 172°C, the melting point range would be reported as 170°C ± 2°C.
Remember, the melting point can vary slightly depending on factors such as the purity of the substance and the rate of heating. It is important to minimize these variables as much as possible to obtain accurate results. Additionally, it is always a good practice to perform the experiment in triplicate to ensure consistency and validate the results.