Calculating the Amount of Solute Required

Oct 13, 2025 by wbrum.org 121 views

Introduction

In chemistry, making a solution of a specific concentration is a common task. To achieve this, we need to know the amount of solute required to make a solution of a particular concentration. In this article, we will discuss how to calculate the amount of 12.0 M HCl needed to make 2.0 L of a 1.0 M solution.

Understanding Molarity

Molarity is a measure of the concentration of a solution, expressed as the number of moles of solute per liter of solution. It is denoted by the symbol 'M'. For example, a 1.0 M solution of HCl means that there is 1 mole of HCl per liter of solution.

Calculating the Amount of Solute Required

To calculate the amount of solute required to make a solution of a specific concentration, we can use the formula:

Molarity (M) = Number of moles of solute / Volume of solution (L)

Rearranging the formula to solve for the number of moles of solute, we get:

Number of moles of solute = Molarity (M) x Volume of solution (L)

Calculating the Amount of 12.0 M HCl Needed

We want to make 2.0 L of a 1.0 M solution of HCl using a 12.0 M solution of HCl. To calculate the amount of 12.0 M HCl needed, we can use the formula:

Number of moles of solute = Molarity (M) x Volume of solution (L)

In this case, the molarity of the solution we want to make is 1.0 M, and the volume of the solution is 2.0 L. The molarity of the 12.0 M HCl solution is 12.0 M.

Number of moles of solute = 1.0 M x 2.0 L = 2.0 moles

Converting Moles to Mass

To find the mass of the solute required, we need to convert the number of moles to mass. The molar mass of HCl is 36.46 g/mol.

Mass of solute = Number of moles x Molar mass

Mass of solute = 2.0 moles x 36.46 g/mol = 72.92 g

Calculating the Volume of 12.0 M HCl Needed

To find the volume of the 12.0 M HCl solution needed, we can use the formula:

Volume of solution = Number of moles of solute / Molarity (M)

In this case, the number of moles of solute is 2.0 moles, and the molarity of the 12.0 M HCl solution is 12.0 M.

Volume of solution = 2.0 moles / 12.0 M = 0.167 L

Conclusion

In conclusion, to make 2.0 L of a 1.0 M solution of HCl using a 12.0 M solution of HCl, we need to calculate the amount of 12.0 M HCl required. We can use the formula:

Number of moles of solute = Molarity (M) x Volume of solution (L)

To find the mass of the solute required, we need to convert the number of moles to mass. The molar mass of HCl is 36.46 g/mol.

Mass of solute = Number of moles x Molar mass

Mass of solute = 2.0 moles x 36.46 g/mol = 72.92 g

To find the volume of the 12.0 M HCl solution needed, we can use the formula:

Volume of solution = Number of moles of solute / Molarity (M)

Volume of solution = 2.0 moles / 12.0 M = 0.167 L

Therefore, to make 2.0 L of a 1.0 M solution of HCl using a 12.0 M solution of HCl, we need 72.92 g of 12.0 M HCl, which is equivalent to 0.167 L of the 12.0 M HCl solution.

Frequently Asked Questions

Q: What is molarity?

A: Molarity is a measure of the concentration of a solution, expressed as the number of moles of solute per liter of solution.

Q: How do I calculate the amount of solute required to make a solution of a specific concentration?

A: To calculate the amount of solute required, you can use the formula:

Number of moles of solute = Molarity (M) x Volume of solution (L)

Q: How do I convert moles to mass?

A: To convert moles to mass, you can use the formula:

Mass of solute = Number of moles x Molar mass

Q: How do I calculate the volume of the solute solution needed?

A: To calculate the volume of the solute solution needed, you can use the formula:

Volume of solution = Number of moles of solute / Molarity (M)

References

[1] "Molarity." Wikipedia, Wikimedia Foundation, 2023, en.wikipedia.org/wiki/Molarity.
[2] "Molarity Formula." Chemistry LibreTexts, Libretexts, 2023, chem.libretexts.org/Bookshelves/General_Chemistry/Book%3A_General_Chemistry_(OpenStax)/07%3A_Solutions/7.3%3A_Molarity.
[3] "Molarity and Mole Fraction." Chemistry LibreTexts, Libretexts, 2023, chem.libretexts.org/Bookshelves/General_Chemistry/Book%3A_General_Chemistry_(OpenStax)/07%3A_Solutions/7.3%3A_Molarity.

Introduction

In our previous article, we discussed how to calculate the amount of 12.0 M HCl needed to make 2.0 L of a 1.0 M solution. We also provided a step-by-step guide on how to convert moles to mass and calculate the volume of the solute solution needed. In this article, we will answer some frequently asked questions related to calculating the amount of solute required to make a solution of a specific concentration.

Q&A

Q: What is the difference between molarity and molality?

A: Molarity is a measure of the concentration of a solution, expressed as the number of moles of solute per liter of solution. Molality, on the other hand, is a measure of the concentration of a solution, expressed as the number of moles of solute per kilogram of solvent.

Q: How do I calculate the amount of solute required to make a solution of a specific concentration if I don't know the molarity of the solute solution?

A: To calculate the amount of solute required, you can use the formula:

Number of moles of solute = Molarity (M) x Volume of solution (L)

However, if you don't know the molarity of the solute solution, you can use the formula:

Molarity (M) = Number of moles of solute / Volume of solution (L)

To find the molarity of the solute solution, you can use a titration method or a spectrophotometric method.

Q: How do I calculate the amount of solute required to make a solution of a specific concentration if I don't know the volume of the solution?

A: To calculate the amount of solute required, you can use the formula:

Number of moles of solute = Molarity (M) x Volume of solution (L)

However, if you don't know the volume of the solution, you can use the formula:

Molarity (M) = Number of moles of solute / Volume of solution (L)

To find the volume of the solution, you can use a volumetric flask or a pipette.

Q: How do I convert moles to mass if I don't know the molar mass of the solute?

A: To convert moles to mass, you can use the formula:

Mass of solute = Number of moles x Molar mass

However, if you don't know the molar mass of the solute, you can look it up in a reference book or online database.

Q: How do I calculate the volume of the solute solution needed if I don't know the number of moles of solute?

A: To calculate the volume of the solute solution needed, you can use the formula:

Volume of solution = Number of moles of solute / Molarity (M)

However, if you don't know the number of moles of solute, you can use the formula:

Molarity (M) = Number of moles of solute / Volume of solution (L)

To find the number of moles of solute, you can use a titration method or a spectrophotometric method.

Conclusion

In conclusion, calculating the amount of solute required to make a solution of a specific concentration can be a complex task. However, by using the formulas and methods outlined in this article, you can easily calculate the amount of solute required. Remember to always check your units and to use the correct formulas to avoid errors.

Frequently Asked Questions

Q: What is the difference between a strong acid and a weak acid?

A: A strong acid is an acid that completely dissociates in water, while a weak acid is an acid that only partially dissociates in water.

Q: How do I calculate the pH of a solution?

A: To calculate the pH of a solution, you can use the formula:

pH = -log[H+]

Where [H+] is the concentration of hydrogen ions in the solution.

Q: How do I calculate the pOH of a solution?

A: To calculate the pOH of a solution, you can use the formula:

pOH = -log[OH-]

Where [OH-] is the concentration of hydroxide ions in the solution.

References

[1] "Molarity." Wikipedia, Wikimedia Foundation, 2023, en.wikipedia.org/wiki/Molarity.
[2] "Molarity Formula." Chemistry LibreTexts, Libretexts, 2023, chem.libretexts.org/Bookshelves/General_Chemistry/Book%3A_General_Chemistry_(OpenStax)/07%3A_Solutions/7.3%3A_Molarity.
[3] "Molarity and Mole Fraction." Chemistry LibreTexts, Libretexts, 2023, chem.libretexts.org/Bookshelves/General_Chemistry/Book%3A_General_Chemistry_(OpenStax)/07%3A_Solutions/7.3%3A_Molarity.