In recrystalization of acetanilide if your percentage yield is greater than 100% how would this occur?

The ppt could be wet or even impure.

The purpose of crystallization is to remind impurities. So, I doubt if that is what happend. My guess is that you messed up on your calculations and your initial weight of acetanililde was incorrectly begin with.

If the percentage yield of a recrystallization process is greater than 100%, it indicates that the actual yield (the mass of the purified acetanilide obtained) is higher than the theoretical yield (the maximum possible mass of purified acetanilide based on the starting material). This situation may occur due to various factors:

1. Contamination: If impurities are present in the starting material, they can add additional mass to the final product, leading to a higher measured yield.

2. Solvent retention: If the final product retains some solvent molecules on its crystal lattice, the mass of the product will be increased, resulting in a greater yield when compared to the theoretical value.

3. Experimental error: Mistakes in measuring masses, transferring the product, or calculating the yield can also lead to an artificially high percentage yield.

It's important to note that a yield greater than 100% is not physically possible and usually indicates errors in the experimental procedure or calculations. In reality, theoretical yield serves as a limit, and the actual yield should not exceed it.

If the percentage yield of a recrystallization process is greater than 100%, it suggests that more product has been obtained than theoretically possible. Although achieving a yield higher than 100% is not physically possible, there are a few factors that could lead to this apparent discrepancy:

1. Impurities in the crude sample: If the initial sample used for recrystallization contains impurities, these impurities could be contributing to the total weight of the final product. Therefore, the weight of the crude sample, including impurities, should be considered when calculating the percentage yield.

2. Moisture content: If the final product retains a significant amount of moisture, it can contribute to the higher weight measurement and falsely elevate the yield percentage. It is crucial to ensure the product is dry and free of any residual water before weighing.

3. Incomplete drying: If the product is not adequately dried, it may contain residual solvents or impurities, resulting in a higher measured weight and consequently an inflated yield calculation.

To avoid these issues and accurately determine the yield, consider the following steps:

1. Use a suitable method to determine the purity of the product, such as TLC or melting point analysis. This will provide insights into the presence of impurities.

2. Thoroughly dry the product after recrystallization to remove any moisture or residual solvents. Utilize appropriate drying techniques, such as vacuum drying or air drying under controlled conditions.

3. Ensure that the product is properly weighed on an accurate balance, taking into account any additional weights due to moisture or impurities.

By carefully considering these factors and following proper techniques, it should be possible to obtain an accurate and reasonable percentage yield for the recrystallization process.