5 mL of a 4 M solution is diluted with water to a total volume of 40 mL. What is the new concentration?
Answer and explanation
Correct answer: B. 0.5 M
- Step 1: Moles are conserved on dilution: C1 V1 = C2 V2.
- Step 2: C2 = 4 x 5 / 40 = 0.5 M.
Answer
0.5 M.
Why not the others: Dilution lowers the concentration, so the answer must be smaller than the original; the other values invert the volumes or skip the division.
Practise more Quantities and solutions.
Free questions with an explanation for every one, and full timed Bagrut (Secondary School Matriculation) mock tests.
More Quantities and solutions questions
- How many moles are in 490 g of H2SO4? (molar mass 98 g/mol)
- 540 g of glucose (molar mass 180 g/mol) are dissolved in water to make 4 L of solution. What is the molarity?
- 5 mL of a 2 M solution is diluted with water to a total volume of 20 mL. What is the new concentration?
- Hydrogen burns in oxygen according to 2 H2 + O2 -> 2 H2O. How many grams of water form when 10 g of hydrogen (H2, 2 g/mol) react completely?ā¦
- 20 mL of 0.1 M HCl is exactly neutralized by 10 mL of NaOH solution. What is the concentration of the NaOH?
- How many moles are in 36 g of H2O? (molar mass 18 g/mol)