1.
Molarity Calculation
Problem: What is the molarity of a solution prepared by dissolving 10 grams of NaCl in 500 mL
of water? (Molar mass of NaCl = 58.44 g/mol)
Answer: Molarity = (10 g / 58.44 g/mol) / 0.5 L = 0.342 M
2. Molarity Calculation
Problem: If you have a 2 L solution with 0.5 moles of KNO₃, what is its molarity?
Answer: Molarity = 0.5 moles / 2 L = 0.25 M
3. Molality Calculation
Problem: Find the molality of a solution with 5 moles of glucose in 500 g of water. (Molar mass
of glucose = 180 g/mol)
Answer: Molality = 5 moles / 0.5 kg = 10 mol/kg
4. Percent Solution Calculation
Problem: What is the percent by mass of a solution containing 20 g of NaOH dissolved in 180 g
of water?
Answer: Percent by mass = (20 g / (20 g + 180 g)) × 100% = 10%
5. Volume Percentage Calculation
Problem: A solution contains 150 mL of ethanol in 850 mL of water. What is the volume
percentage of ethanol?
Answer: Volume percentage = (150 mL / 1000 mL) × 100% = 15%
6. Molarity Calculation
Problem: How many moles of H₂SO₄ are present in 250 mL of a 0.4 M solution?
Answer: Moles = 0.4 M × 0.250 L = 0.1 moles
7. Dilution Calculation
Problem: What is the final concentration when 100 mL of a 6 M solution is diluted to 500 mL?
Answer: Final concentration = (6 M × 100 mL) / 500 mL = 1.2 M
8. Molality Calculation
Problem: Calculate the molality of a solution made by dissolving 8 moles of NaCl in 1 kg of
water.
Answer: Molality = 8 moles / 1 kg = 8 mol/kg
9. Percent Solution Calculation
Problem: What is the percent by volume of a solution with 200 mL of acetone in a total volume
of 800 mL?
Answer: Percent by volume = (200 mL / 800 mL) × 100% = 25%
10. Molarity Calculation
Problem: What is the molarity of a solution containing 15 grams of KCl in 250 mL of solution?
(Molar mass of KCl = 74.55 g/mol)
Answer: Molarity = (15 g / 74.55 g/mol) / 0.250 L = 0.802 M
11. Dilution Calculation
Problem: How many milliliters of a 0.5 M solution are needed to prepare 200 mL of a 0.1 M
solution?
Answer: Volume = (0.1 M × 200 mL) / 0.5 M = 40 mL
12. Molality Calculation
Problem: Find the molality of a solution made by dissolving 2 moles of NaOH in 500 g of
water.
Answer: Molality = 2 moles / 0.5 kg = 4 mol/kg
13. Percent Solution Calculation
Problem: What is the percent by mass of a solution with 12 g of Na₂SO₄ in 288 g of water?
Answer: Percent by mass = (12 g / (12 g + 288 g)) × 100% = 4%
14. Volume Percentage Calculation
Problem: A solution has 250 mL of methanol in a total volume of 750 mL. What is the volume
percentage of methanol?
Answer: Volume percentage = (250 mL / 750 mL) × 100% = 33.33%
15. Molarity Calculation
Problem: Calculate the molarity of a solution prepared by dissolving 20 grams of KBr in 400
mL of water. (Molar mass of KBr = 119.00 g/mol)
Answer: Molarity = (20 g / 119.00 g/mol) / 0.400 L = 0.42 M
16. Dilution Calculation
Problem: How would you prepare 1 L of a 0.25 M NaCl solution from a 2 M NaCl stock
solution?
Answer: Volume needed = (0.25 M × 1 L) / 2 M = 0.125 L or 125 mL
17. Molality Calculation
Problem: What is the molality of a solution made by dissolving 10 moles of urea in 800 g of
water?
Answer: Molality = 10 moles / 0.8 kg = 12.5 mol/kg
18. Percent Solution Calculation
Problem: What is the percent by mass of a solution containing 50 g of NaOH in 450 g of
solution?
Answer: Percent by mass = (50 g / 450 g) × 100% = 11.11%
19. Molarity Calculation
Problem: What is the molarity of a solution prepared by dissolving 25 grams of HCl in 500 mL
of solution? (Molar mass of HCl = 36.46 g/mol)
Answer: Molarity = (25 g / 36.46 g/mol) / 0.500 L = 1.37 M
20. Volume Percentage Calculation
Problem: What is the volume percentage of a solution with 120 mL of solute in 600 mL of total
solution?
Answer: Volume percentage = (120 mL / 600 mL) × 100% = 20%
I hope these problems and solutions help! If you have any more questions or need further
explanations, feel free to ask.
