Benzanilide Molecular Weight: A Comprehensive Guide

The molecular weight of a compound refers to the sum of the atomic weights of all the atoms in one molecule of that compound. Determining the molecular weight is crucial for various chemical calculations and understanding the properties of a substance. This article delves into the molecular weight of benzanilide, exploring its significance and providing practical information.

What is Benzanilide?

Benzanilide (C6H5CONHC6H5) is an organic compound belonging to the amide functional group. It is a white crystalline solid with a faint odor and low solubility in water. Benzanilide is commonly used as an intermediate in the synthesis of other organic compounds, such as pharmaceuticals, dyes, and plastics.

Molecular Weight of Benzanilide

The molecular weight of benzanilide is calculated by adding the atomic weights of its constituent atoms:

• Carbon (C): 6 x 12.011 amu = 72.066 amu
• Hydrogen (H): 10 x 1.008 amu = 10.080 amu
• Nitrogen (N): 1 x 14.007 amu = 14.007 amu
• Oxygen (O): 1 x 16.000 amu = 16.000 amu

Total molecular weight: 72.066 amu + 10.080 amu + 14.007 amu + 16.000 amu = 183.153 amu

According to the PubChem database, the exact molecular weight of benzanilide is 183.2094 amu. This value considers the isotopic distribution of the elements involved.

Significance of Molecular Weight

Knowing the molecular weight of benzanilide is important for several reasons:

• Stoichiometry Calculations: Molecular weight allows for the determination of the stoichiometric ratios of reactants and products in chemical reactions.
• Solubility and Properties: Molecular weight influences the solubility and other physical properties of a compound.
• Spectroscopy: Molecular weight helps in interpreting mass spectrometry and NMR spectroscopy data.
• Synthesis and Purity: Molecular weight is crucial for optimizing synthesis reactions and assessing the purity of the final product.

Tables

Table 1: Atomic Weights of Elements in Benzanilide

Table 2: Molecular Weight of Benzanilide

Table 3: Properties of Benzanilide

Stories

Story 1: The Misidentified Amide

A chemist was working on a project involving the synthesis of an amide. After completing the reaction, they sent the product to be analyzed by mass spectrometry. However, the results indicated a molecular weight that did not match any known amides. After much investigation, it was discovered that an error had occurred during reagent preparation, and the compound synthesized was not an amide at all.

What We Learn: It is always important to double-check the identity of chemicals before using them in reactions.

Story 2: The Lost Solvent

A student was performing a purification step that involved dissolving the crude product in a solvent. After filtration, the solvent was evaporated, but the mass of the resulting product was significantly lower than expected. It was later discovered that the solvent had been inadvertently poured out along with the filtrate.

What We Learn: Always use a clean funnel for filtration and be aware of how much solvent you are using.

Story 3: The Overlooked Decimal Point

A researcher was working on a project that required precise stoichiometry. While calculating the amount of reagent to use, they accidentally overlooked a decimal point in the molecular weight of benzanilide. As a result, they added an incorrect amount of reagent, leading to an incorrect reaction yield.

What We Learn: Pay close attention to units and decimal points when performing calculations.

Common Mistakes to Avoid

• Confusing Molecular Weight with Molar Mass: Molecular weight is expressed in atomic mass units (amu), while molar mass refers to the mass of one mole of a substance in grams.
• Using Incorrect Atomic Weights: Always use the most up-to-date atomic weights to ensure accurate calculations.
• Neglecting Isotopes: The molecular weight of benzanilide considers the isotopic distribution, so it is slightly higher than the sum of the atomic weights.
• Mixing Units: Be consistent with the units used for molecular weight (amu or g/mol).

Pros and Cons of Benzanilide

Pros:

• Versatile intermediate for organic synthesis
• Used in pharmaceuticals, dyes, and plastics industry
• Relatively low toxicity compared to other amides

Cons:

• Limited solubility in water
• Can be irritating to the skin and eyes
• Can undergo hydrolysis under acidic or basic conditions

Conclusion

The molecular weight of benzanilide, 183.2094 amu, plays a crucial role in chemical calculations and understanding its properties. By accurately determining molecular weight, researchers and chemists can optimize reactions, analyze data, and ensure the quality and purity of their products. This article provides comprehensive information on the molecular weight of benzanilide, emphasizing its significance and guiding readers on how to avoid common pitfalls.