Question 2: How Many Grams Of Hydrochloric Acid ($HCl, M = 36.46 \mathrm{g}/\mathrm{mol}$) Are Needed To Prepare 100.0 ML Of A $0.500 \mathrm{M} \mathrm{HCl}$ Solution?A) 0.182 G B) 1.82 G C) 3.65 G D) 18.2 G E) 0.365 G

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Understanding the Problem

To prepare a solution of a specific concentration, we need to know the amount of solute required. In this case, we are tasked with determining the amount of hydrochloric acid (HCl) needed to prepare 100.0 mL of a 0.500 M HCl solution. To solve this problem, we will use the concept of molarity and the formula for calculating the amount of solute required.

Molarity and Its Formula

Molarity is a measure of the concentration of a solution, expressed as the number of moles of solute per liter of solution. The formula for molarity is:

M = n/V

where:

  • M = molarity (in moles per liter, M)
  • n = number of moles of solute
  • V = volume of the solution (in liters, L)

Calculating the Number of Moles of HCl Required

To calculate the number of moles of HCl required, we need to multiply the molarity of the solution by the volume of the solution in liters. The molarity of the solution is given as 0.500 M, and the volume of the solution is 100.0 mL, which is equivalent to 0.100 L.

n = M x V = 0.500 M x 0.100 L = 0.0500 mol

Calculating the Mass of HCl Required

To calculate the mass of HCl required, we need to multiply the number of moles of HCl by the molar mass of HCl. The molar mass of HCl is given as 36.46 g/mol.

m = n x M = 0.0500 mol x 36.46 g/mol = 1.823 g

Rounding the Answer

Rounding the answer to two significant figures, we get:

m ≈ 1.82 g

Conclusion

In conclusion, to prepare 100.0 mL of a 0.500 M HCl solution, we need approximately 1.82 g of hydrochloric acid.

Answer

The correct answer is B) 1.82 g.

Additional Information

  • The molar mass of HCl is 36.46 g/mol.
  • The volume of the solution is 100.0 mL, which is equivalent to 0.100 L.
  • The molarity of the solution is 0.500 M.
  • The number of moles of HCl required is 0.0500 mol.
  • The mass of HCl required is 1.823 g.
    Frequently Asked Questions (FAQs) About Calculating the Amount of Hydrochloric Acid Needed for a Solution =============================================================================================

Q: What is molarity, and how is it related to the amount of solute required?

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

M = n/V

where:

  • M = molarity (in moles per liter, M)
  • n = number of moles of solute
  • V = volume of the solution (in liters, L)

To calculate the amount of solute required, we need to multiply the molarity of the solution by the volume of the solution in liters.

Q: How do I calculate the number of moles of HCl required to prepare a solution?

A: To calculate the number of moles of HCl required, we need to multiply the molarity of the solution by the volume of the solution in liters. The molarity of the solution is given as 0.500 M, and the volume of the solution is 100.0 mL, which is equivalent to 0.100 L.

n = M x V = 0.500 M x 0.100 L = 0.0500 mol

Q: What is the molar mass of HCl, and how is it used to calculate the mass of HCl required?

A: The molar mass of HCl is 36.46 g/mol. To calculate the mass of HCl required, we need to multiply the number of moles of HCl by the molar mass of HCl.

m = n x M = 0.0500 mol x 36.46 g/mol = 1.823 g

Q: How do I round the answer to two significant figures?

A: To round the answer to two significant figures, we need to look at the third significant figure, which is 3 in this case. Since the third significant figure is less than 5, we round down to 1.82 g.

Q: What are some common mistakes to avoid when calculating the amount of solute required?

A: Some common mistakes to avoid when calculating the amount of solute required include:

  • Not converting the volume of the solution from milliliters to liters
  • Not multiplying the molarity of the solution by the volume of the solution in liters
  • Not using the correct molar mass of the solute
  • Not rounding the answer to the correct number of significant figures

Q: What are some real-world applications of calculating the amount of solute required?

A: Some real-world applications of calculating the amount of solute required include:

  • Preparing solutions for laboratory experiments
  • Preparing medications for patients
  • Preparing cleaning solutions for industrial applications
  • Preparing food and beverages for consumption

Q: How can I practice calculating the amount of solute required?

A: You can practice calculating the amount of solute required by:

  • Using online calculators or software to practice solving problems
  • Working with a partner or group to practice solving problems together
  • Creating your own practice problems and solutions
  • Reviewing and practicing with past exams or quizzes

Conclusion

Calculating the amount of solute required is an important skill in chemistry and other fields. By understanding the concept of molarity and the formula for calculating the amount of solute required, you can accurately prepare solutions for a variety of applications. Remember to avoid common mistakes and practice regularly to improve your skills.