Examples of Dilution Calculations in Chemistry

🧪 Quick Study Guide

• 🧮 Dilution Definition: Dilution is the process of reducing the concentration of a solute in a solution, usually by adding more solvent.
• ⚗️ The Dilution Equation: The key formula for dilution calculations is $M_1V_1 = M_2V_2$, where:
  • $M_1$ = Initial concentration (Molarity)
  • $V_1$ = Initial volume
  • $M_2$ = Final concentration (Molarity)
  • $V_2$ = Final volume
• 🔢 Units: Volume units ($V_1$ and $V_2$) must be the same (e.g., both in mL or both in L). Concentration units ($M_1$ and $M_2$) also need to be consistent.
• 💡 Dilution Factor: The dilution factor is the ratio of the final volume to the initial volume ($V_2/V_1$). It indicates how much the solution was diluted.
• 📝 Step-by-Step Approach:
  1. Identify the knowns ($M_1$, $V_1$, $M_2$, or $V_2$).
  2. Write down the dilution equation.
  3. Substitute the known values into the equation.
  4. Solve for the unknown variable.

Practice Quiz

1. What is the final concentration when 50.0 mL of a 2.0 M NaCl solution is diluted to 250.0 mL?
   1. 0.4 M
   2. 1.0 M
   3. 2.0 M
   4. 10.0 M
2. What volume of a 5.0 M stock solution is required to prepare 100.0 mL of a 0.25 M solution?
   1. 2.0 mL
   2. 5.0 mL
   3. 10.0 mL
   4. 20.0 mL
3. If you dilute 20.0 mL of a 3.0 M solution to a final volume of 60.0 mL, what is the molarity of the diluted solution?
   1. 1.0 M
   2. 2.0 M
   3. 6.0 M
   4. 9.0 M
4. A chemist needs to prepare 500.0 mL of a 0.1 M solution from a 1.0 M stock solution. What volume of the stock solution is required?
   1. 5.0 mL
   2. 50.0 mL
   3. 100.0 mL
   4. 250.0 mL
5. You have 25 mL of a 4.0 M solution. You add 75 mL of solvent. What is the new concentration?
   1. 1.0 M
   2. 2.0 M
   3. 8.0 M
   4. 12.0 M
6. What is the dilution factor when 10 mL of solution is diluted to 100 mL?
   1. 0.1
   2. 1
   3. 10
   4. 100
7. 50 mL of 3.0 M HCl is mixed with 150 mL of water. What is the molarity of the resulting solution?
   1. 0.5 M
   2. 0.75 M
   3. 1.0 M
   4. 1.5 M