Example of a laboratory experiment report on determining the purity of a substance by using melting point.

Title: Determining the Purity of Acetaminophen Using Melting Point Analysis

Objective:
The objective of this experiment is to determine the purity of a sample of acetaminophen by using melting point analysis.

Materials:
- Sample of acetaminophen
- Melting point apparatus
- Capillary tubes
- Thermometer
- Heating source

Procedure:
1. The melting point apparatus was set up according to the manufacturer's instructions.
2. A small amount of acetaminophen was placed in a capillary tube and the tube was inserted into the melting point apparatus.
3. The heating source was turned on and the temperature was slowly increased until the acetaminophen began to melt.
4. The temperature at which the first drop of liquid appeared was recorded as the melting point of the acetaminophen.
5. The experiment was repeated two more times with fresh samples of acetaminophen to ensure accuracy.

Results:
- The melting point of the first sample of acetaminophen was recorded as 169°C.
- The melting point of the second sample of acetaminophen was recorded as 170°C.
- The melting point of the third sample of acetaminophen was recorded as 168°C.

Discussion:
The melting point of pure acetaminophen is known to be 169-171°C. Based on the results of this experiment, it can be concluded that the sample of acetaminophen used was of high purity, as the melting points obtained were within the expected range. The small variations in the melting points could be due to experimental error or impurities present in the sample.

Conclusion:
The purity of the acetaminophen sample was determined to be high based on the melting point analysis. Further experiments could be conducted to confirm the purity of the sample using other analytical techniques.

Laboratory Experiment Report

Title: Determination of Substance Purity Using Melting Point

Objective:

- To determine the purity of an unknown substance by measuring its melting point.

Materials:

- Unknown substance
- Melting point apparatus
- Thermometer
- Capillary tube

Procedure:

1. Prepare the capillary tube:
- Cut a piece of capillary tube approximately 3-4 cm long.
- Seal one end of the tube by heating it over a flame.
2. Prepare the substance:
- Grind the unknown substance into a fine powder.
- Pack the powder tightly into the open end of the capillary tube, leaving a small amount of space at the top.
3. Attach the thermometer:
- Suspend the capillary tube in the melting point apparatus.
- Insert a thermometer into the apparatus and position its bulb close to the sample.
4. Raise the temperature:
- Gradually heat the apparatus using a heating mantle or hot water bath.
- Record the temperature when the substance begins to melt.
5. Measure the melting point:
- Continue heating until the substance is completely melted.
- Record the temperature when the last traces of the substance melt.
6. Calculate the purity:
- Compare the measured melting point to the literature value for the pure substance.
- The purity can be estimated using the following formula:

```
Purity (%) = (Measured Melting Point / Literature Melting Point) x 100
```

Results:

| Substance | Melting Point (°C) | Literature Melting Point (°C) | Purity (%) |
|---|---|---|---|
| Unknown Substance | 152.0 | 153.5 | 98.4 |

Discussion:

The measured melting point of the unknown substance was 152.0 °C, while the literature melting point of the pure substance is 153.5 °C. Using the formula above, the purity of the unknown substance was calculated to be 98.4%. This indicates that the substance is relatively pure, with only a small amount of impurities present.

Conclusion:

The melting point determination experiment successfully demonstrated the method for estimating the purity of an unknown substance. By comparing the measured melting point to the literature value, it was possible to determine that the unknown substance had a purity of 98.4%. This information can be useful for quality control or research purposes.