Calculating the Mass of Sodium Chloride (NaCl) in Grams from Moles

Objective: To understand how to calculate the mass of sodium chloride (NaCl) in grams using the concept of moles and molar mass.

Introduction

This guide will walk you through the process of determining the mass of NaCl in grams using a given number of moles. Sodium chloride (NaCl) is a commonly used compound in laboratory and industrial applications. Understanding how to perform such calculations is essential for professionals and students in chemistry, as it forms the basis of many chemical processes and experiments.

Step-by-Step Calculation

To find the number of grams in 0.45 moles of sodium chloride (NaCl), you can use the concept of molar mass. Here is how you can do it:

Step 1: Determine the Molar Mass of NaCl

The molar mass of a substance is the mass of one mole of that substance. For NaCl, you need to add the atomic masses of sodium (Na) and chlorine (Cl).

Sodium (Na): Atomic mass 22.99 g/mol

Chlorine (Cl): Atomic mass 35.45 g/mol

Therefore, the molar mass of NaCl is calculated as follows:

Molar mass of NaCl Mass of Na Mass of Cl 22.99 g/mol 35.45 g/mol 58.44 g/mol

Step 2: Calculate the Mass of 0.45 Moles of NaCl

Once you have the molar mass, you can use the formula to find the mass of the given number of moles:

mass number of moles times; molar mass

Plugging in the values:

mass 0.45 moles times; 58.44 g/mol ≈ 26.298 g

When rounded to three significant figures, the mass of 0.45 moles of NaCl is approximately 26.3 grams.

Further Explanation

To understand the calculation further, consider the molecular mass of Na and Cl:

Molecular Mass of NaCl 23 g 35 g 58 g/mole

Thus, the number of grams of NaCl can be calculated as:

Grams of NaCl 0.45 moles times; 58.45 g/mole ≈ 26.3 g

Common Formula for Moles to Grams

The general formula used for converting moles to grams is:

Number of moles Given mass of substance / Molar mass of substance

Therefore, for NaCl at 0.45 moles, the calculation will be:

Number of moles 0.45 times; 58.5 g/mole 26.31 g

Conclusion

Understanding and applying the concept of molar mass and the mole-to-gram conversion proves to be a crucial skill in chemistry. By following the steps outlined in this guide, you should be able to confidently calculate the mass of any substance given its moles and molar mass.

Remember, practice and repetition are key to mastering these calculations. If you have further questions or need assistance, feel free to consult your textbook, online resources, or seek guidance from your instructor.