Mastering Dilution Calculations in Chemistry

This tutorial from The Chemistry Solution covers dilution problems, focusing on the relationship between concentration and volume. It explains the equation m1v1 = m2v2, emphasizing the importance of consistent units for accurate calculations. Two examples are provided: one calculating the volume of a diluted NaOH solution and another finding the final concentration of a diluted HCl solution. The tutorial highlights the need to convert units when necessary to ensure they match, allowing for correct application of the dilution equation.

What happens to the number of moles of solute when a solution is diluted?

• It remains the same.

• It decreases.

• It increases.

• It doubles.

Which equation represents the relationship between initial and final concentrations and volumes in a dilution?

• m1 + v1 = m2 + v2

• m1 - v1 = m2 - v2

• m1v1 = m2v2

• m1/v1 = m2/v2

Why is it important for initial and final concentrations to have the same units?

• To make the solution more concentrated.

• To ensure the equation m1v1 = m2v2 is valid.

• To decrease the number of moles of solute.

• To increase the volume of the solution.

What must be true about the units of initial and final volumes in a dilution problem?

• They must be in liters.

• They must be in milliliters.

• They must be different.

• They must have the same units.

In the first example, what is the final volume of the diluted NaOH solution?

• 525 milliliters

• 31.5 milliliters

• 0.150 liters

• 2.5 liters

How many milliliters of a 2.5 molar NaOH solution are needed to make 525 milliliters of a 0.15 molar solution?

• 52.5 milliliters

• 150 milliliters

• 31.5 milliliters

• 525 milliliters

In the second example, what is the initial concentration of the HCl solution?

• 6 molar

• 0.250 molar

• 1.08 molar

• 0.150 molar

What is the final concentration of the HCl solution after dilution in the second example?

• 6 molar

• 1.08 molar

• 0.150 molar

• 0.250 molar

Why is it necessary to convert units in the second example problem?

• To change the molarity.

• To decrease the volume.

• To ensure volume units cancel out.

• To increase the concentration.

What is the final volume of the HCl solution in the second example?

• 0.250 liters

• 6 liters

• 45 milliliters

• 1.08 liters