Answer: Molar mass of sodium hydroxide (NaOH) is 40.00 g/mol.

Molar Mass of Sodium Hydroxide

Sodium hydroxide (NaOH), commonly known as lye or caustic soda, is a strong base widely used in various industries, including manufacturing, cleaning, and water treatment. It is highly effective in breaking down organic materials and is a key ingredient in soaps and detergents. Understanding its molar mass is essential for calculations in both chemical reactions and industrial applications.

This guide will walk you through how to calculate the molar mass of sodium hydroxide step by step, as well as its significance in chemistry and industry.

Understanding Molar Mass

Molar mass refers to the mass of one mole of a substance, expressed in grams per mole (g/mol). A mole is a fundamental unit in chemistry, representing \(6.022 \times 10^{23}\) particles (atoms, molecules, or ions). The molar mass allows us to convert between the mass of a substance and the number of moles in stoichiometric calculations.

To calculate the molar mass of sodium hydroxide (NaOH), we need to consider the molar masses of sodium (Na), oxygen (O), and hydrogen (H), which are the elements present in NaOH.

Molar Masses of Sodium, Oxygen, and Hydrogen

Here are the molar masses of the elements in sodium hydroxide:

  • Sodium (Na): The molar mass of sodium is approximately 22.99 g/mol.
  • Oxygen (O): The molar mass of oxygen is approximately 16.00 g/mol.
  • Hydrogen (H): The molar mass of hydrogen is approximately 1.008 g/mol.

Sodium hydroxide (NaOH) contains one atom each of sodium, oxygen, and hydrogen, so we will use these values to calculate its molar mass.

Formula for Calculating Molar Mass

The molar mass of a compound is calculated using the following formula:

\[ \text{Molar Mass of Compound} = \sum (\text{Number of Atoms} \times \text{Molar Mass of Element}) \]

For sodium hydroxide (NaOH), the formula becomes:

\[ \text{Molar Mass of NaOH} = (1 \times \text{Molar Mass of Na}) + (1 \times \text{Molar Mass of O}) + (1 \times \text{Molar Mass of H}) \]

Step-by-Step Calculation

Let’s calculate the molar mass of sodium hydroxide step by step:

Step 1: Multiply the molar mass of sodium (Na) by the number of sodium atoms in sodium hydroxide:

\[ 1 \times 22.99 \, \text{g/mol} = 22.99 \, \text{g/mol} \]

Step 2: Multiply the molar mass of oxygen (O) by the number of oxygen atoms in sodium hydroxide:

\[ 1 \times 16.00 \, \text{g/mol} = 16.00 \, \text{g/mol} \]

Step 3: Multiply the molar mass of hydrogen (H) by the number of hydrogen atoms in sodium hydroxide:

\[ 1 \times 1.008 \, \text{g/mol} = 1.008 \, \text{g/mol} \]

Step 4: Add the values from steps 1, 2, and 3 to find the total molar mass of sodium hydroxide:

\[ \text{Molar Mass of NaOH} = 22.99 \, \text{g/mol} + 16.00 \, \text{g/mol} + 1.008 \, \text{g/mol} \]

\[ \text{Molar Mass of NaOH} = 40.00 \, \text{g/mol} \]

Final Molar Mass of Sodium Hydroxide

The molar mass of sodium hydroxide (NaOH) is approximately 40.00 g/mol. This value is essential for many practical uses, such as determining the amount of NaOH needed in chemical reactions, preparing solutions, or calculating concentrations in industrial processes.

Conclusion

The molar mass of sodium hydroxide (NaOH) is 40.00 g/mol, calculated by summing the molar masses of one sodium atom, one oxygen atom, and one hydrogen atom.