Calculating Moles of NaOH in a Given Volume
Calculating Moles of NaOH in a Given Volume
This article explains how to calculate the number of moles of sodium hydroxide (NaOH) in a solution or a solid sample. We will delve into both scenarios, providing clear step-by-step instructions and formulas to help you understand the process.
Moles of NaOH in a Solid Sample
Scenario 1: Sodium Hydroxide as a Solid Sample
If you have a solid piece of sodium hydroxide with a volume of 25 cm3, you can calculate the moles using its density and molar mass.
The first step is to find the mass of the NaOH sample. The density of sodium hydroxide (NaOH) is 2.13 g/cm3. Therefore, for 25 cm3, the mass is calculated as follows:
Mass Volume × Density Mass 25 cm3 × 2.13 g/cm3 53.25 g
Next, use the molar mass of NaOH (40.00 g/mol) to find the number of moles:
Moles Mass / Molar Mass Moles 53.25 g / 40.00 g/mol ≈ 1.33 moles
Moles of NaOH in a Solution
Scenario 2: Sodium Hydroxide in a Solution
For a solution, determining the moles of NaOH requires the concentration (molarity) of the solution. The molarity (M) is defined as the number of moles of solute per liter of solution (M moles/liter).
Let us consider a 0.15 M NaOH solution with a volume of 27 cm3. First, convert the volume to liters:
27 cm3 0.027 L
The number of moles is then calculated as:
M moles / volume in liters 0.15 M moles / 0.027 L Moles 0.15 M × 0.027 L 0.00405 moles
Conclusion and Practical Applications
Understanding how to calculate the number of moles of NaOH in different scenarios is crucial for various applications, from laboratory experiments to industrial processes. The key is to correctly identify whether you are dealing with a solid sample or a solution, and to use the appropriate formulas and conversion factors.
Additional Information
Density: Sodium hydroxide has a density of 2.13 g/cm3, which is an important property for calculating the mass of a given volume.
Molar Mass: The molar mass of NaOH is 40.00 g/mol, which is a fundamental constant for converting mass to moles.
Molarity: Molarity is a measure of concentration that is used widely in chemistry and biochemistry.
Keywords
Keyword 1: Molarity - The concentration of a solution expressed in moles per liter.
Keyword 2: Moles of NaOH - The number of moles of sodium hydroxide in a given sample or solution.
Keyword 3: Chemical Calculation - The process of solving chemical problems using mathematical equations and formulas.