Introduction

Understanding the molecular count in a given substance is a fundamental concept in chemistry, particularly when dealing with compounds like ammonia (NH3). This article will explain how to calculate the number of molecules in 51 grams of NH3 using basic principles of chemistry. We will discuss the steps involved, the significance of Avogadro’s number, and provide a thorough derivation of the solution.

Understanding the Concept

The molar mass of a substance is the mass of one mole of its molecules. Ammonia (NH3) has a molar mass of approximately 17 grams per mole. This means that one mole of NH3 contains 6.023 x 1023 molecules, a quantity known as Avogadro’s number.

Calculating the Number of Moles of NH3

To determine the number of moles of NH3 in 51 grams, we use the formula:

No. of moles of NH3 weight in grams / molar mass

Given that the molar mass of NH3 is 17 grams per mole, we can calculate the number of moles as follows:

No. of moles of NH3 51 g / 17 g/mol 3 moles

Calculating the Number of Molecules in 3 Moles of NH3

Once we have the number of moles, we can find the total number of molecules using Avogadro’s number. Avogadro's number (NA) is 6.023 x 1023 molecules per mole. Therefore:

No. of molecules in 3 moles of NH3 3 x 6.023 x 1023 1.8069 x 1024 molecules

Step-by-Step Calculation

Step 1: Determine the molar mass of NH3.

Step 2: Calculate the number of moles in 51 grams of NH3.

Nmoles 51 g / 17 g/mol 3 moles

Step 3: Calculate the number of molecules in 3 moles of NH3.

Nmolecules 3 moles x 6.023 x 1023 molecules/mole 1.8069 x 1024 molecules

Related Concepts and Applications

The ability to count molecules is crucial in various fields, including:

Chemical Engineering: Understanding molecular quantities aids in designing processes for the production and purification of chemicals. Biochemistry: Knowing the number of molecules in biological systems is vital for understanding cellular processes and metabolic pathways. Materials Science: The number of molecules can influence the properties of materials at a microscopic level.

Understanding the molecular count in substances like NH3 is not just a theoretical exercise; it has practical applications in fields ranging from pharmaceuticals to environmental science.

Conclusion

In conclusion, the number of molecules in 51 grams of ammonia (NH3) is approximately 1.8069 x 1024 molecules. By applying basic principles of chemistry and Avogadro’s number, we can accurately determine molecular counts, which is essential for both scientific research and practical applications.

Stay tuned for more articles on chemistry and molecular science.