Answer: 400 mL.
- A 300 mL
- B 400 mL
- C 500 mL
- D 100 mL
Correct answer: B. 400 mL
Explanation: Using M1V1 = M2V2: 0.5 x 100 = 0.1 x V2, so V2 = 500 mL total. Water to be added = 500 - 100 = 400 mL.
Mass connects to moles via molar mass, and moles connect to particle count via Avogadro's number or to gas volume via the 22.4 L/mol rule at STP.
Concept context
The mole is chemistry's counting unit. Learn to relate mass, volume, and number of particles using Avogadro's number and molar mass, the foundation of all stoichiometry and reaction calculations.