Molar Mass Of E Stilbene

Understanding the Molar Mass of E-Stilbene: A Comprehensive Guide

E-stilbene, also known as trans-stilbene, is an organic compound with a fascinating structure and significant applications in various fields. Understanding its molar mass is crucial for numerous chemical calculations and experiments. This article will delve into the detailed calculation, significance, and applications of determining the molar mass of E-stilbene, providing a comprehensive understanding suitable for students and researchers alike.

Introduction

Molar mass, often mistakenly referred to as molecular weight, represents the mass of one mole of a substance. A mole is a fundamental unit in chemistry, representing Avogadro's number (approximately 6.022 x 10²³) of particles (atoms, molecules, ions, etc.). For E-stilbene, determining its molar mass involves understanding its chemical formula and the atomic masses of its constituent elements. This value is essential for stoichiometric calculations, determining concentrations, and understanding the properties of this important organic compound. This guide will walk you through the process step-by-step, explaining the underlying principles and highlighting the importance of accuracy in molar mass calculations.

Determining the Chemical Formula of E-Stilbene

Before calculating the molar mass, we need to establish the chemical formula of E-stilbene. E-stilbene, (E)-1,2-diphenylethene, possesses a distinctive structure featuring two phenyl rings connected by a carbon-carbon double bond. The "E" configuration indicates that the larger substituents (phenyl groups) are on opposite sides of the double bond, a trans configuration. This configuration is crucial as it affects the compound's physical and chemical properties. Its chemical formula is C₁₄H₁₂. This representation clearly shows that each molecule of E-stilbene contains 14 carbon atoms and 12 hydrogen atoms.

Calculating the Molar Mass of E-Stilbene

Calculating the molar mass involves summing the atomic masses of all the atoms present in the molecule. We use the standard atomic weights of carbon (C) and hydrogen (H) which can be found in the periodic table:

• Atomic mass of Carbon (C): Approximately 12.011 g/mol
• Atomic mass of Hydrogen (H): Approximately 1.008 g/mol

Now let's perform the calculation:

1. Carbon contribution: 14 carbon atoms × 12.011 g/mol/carbon atom = 168.154 g/mol
2. Hydrogen contribution: 12 hydrogen atoms × 1.008 g/mol/hydrogen atom = 12.096 g/mol
3. Total molar mass: 168.154 g/mol + 12.096 g/mol = 180.25 g/mol

Therefore, the molar mass of E-stilbene is approximately 180.25 grams per mole. It's important to note that slight variations may occur depending on the source of atomic mass data used, but this value is accurate for most practical purposes.

Significance of Molar Mass in E-Stilbene Applications

The accurately determined molar mass of E-stilbene plays a critical role in numerous applications. Here are some key examples:

• Stoichiometric Calculations: In chemical reactions involving E-stilbene, the molar mass is essential for calculating reactant amounts, product yields, and limiting reagents. This is fundamental for precise synthesis and analysis. Knowing the molar mass allows chemists to convert between grams (mass) and moles (amount of substance), allowing precise control over reaction conditions.

• Solution Preparation: When preparing solutions of E-stilbene, for example, in spectroscopy or other analytical techniques, the molar mass is needed to determine the required mass to obtain a specific molar concentration (molarity). Accuracy in molarity is paramount for reliable experimental results.

• Quantitative Analysis: Techniques like titration and gravimetric analysis heavily rely on molar mass calculations for accurate determination of concentrations and analyte quantities. These methods are often used to assess the purity of synthesized E-stilbene or to determine its concentration in a sample.

• Physical Property Calculations: Understanding the molar mass helps in the calculation and interpretation of various physical properties of E-stilbene, such as density, molar volume, and other thermodynamic properties. These properties are crucial for understanding the behavior of the compound in different conditions.

• Spectroscopic Analysis: While not directly used in the calculation of spectral peaks, the molar mass provides valuable context for interpreting spectroscopic data. It contributes to understanding the relationship between molecular structure and spectral characteristics.

Synthesis and Purification of E-Stilbene: Impact of Molar Mass

The synthesis of E-stilbene often involves the Wittig reaction or other methods producing a mixture of E and Z isomers. Purification is crucial to obtain high-purity E-stilbene for various applications. Techniques like recrystallization and chromatography are employed. Monitoring the purification process often involves weighing the purified product, and subsequently calculating the yield based on the theoretical yield predicted using the molar mass. The purity is also frequently assessed using techniques that require precise molar mass knowledge for accurate interpretation.

Frequently Asked Questions (FAQ)

Q1: What is the difference between molar mass and molecular weight?

A1: While often used interchangeably, molar mass is technically more precise. Molecular weight refers to the mass of a single molecule, while molar mass is the mass of one mole of molecules (Avogadro's number). The units are different – amu (atomic mass units) for molecular weight and g/mol (grams per mole) for molar mass.

Q2: Can I use an approximate value for the atomic masses in the molar mass calculation?

A2: For most general purposes, using approximate atomic masses from the periodic table is sufficient. However, for high-precision work requiring very accurate molar mass determination, using more precise atomic mass values may be necessary. These are available in specialized chemistry handbooks.

Q3: How does the isomerism (E vs Z) affect the molar mass?

A3: The molar mass remains the same for both E-stilbene and Z-stilbene (Z-stilbene, or cis-stilbene) as both isomers have the same chemical formula, C₁₄H₁₂. Only the arrangement of atoms differs, not the total number of atoms.

Q4: What are the common sources of error in molar mass determination?

A4: Common sources of error can include inaccurate weighing of the sample, impurities in the sample, and using outdated or imprecise atomic mass values. Careful experimental techniques and high-quality reagents are essential to minimize these errors.

Conclusion

The accurate determination of the molar mass of E-stilbene is critical for various aspects of its study and application. The calculation, though seemingly straightforward, underlies many quantitative analyses and reactions involving this important organic compound. Understanding the process and significance of molar mass calculations provides a strong foundation for further studies in organic chemistry and related fields. This comprehensive guide aims to equip students and researchers with a thorough understanding of the calculation, significance, and practical applications of the molar mass of E-stilbene, fostering a deeper appreciation for this fundamental concept in chemistry. By carefully following the steps and understanding the underlying principles, one can confidently calculate and utilize the molar mass of E-stilbene in various scientific endeavors.