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NDA 2025 GAT · General Knowledge · Mole Concept and States of Matter · hard

What is the mass of 0.25 mole of calcium carbonate, CaCO3? (Atomic masses: Ca = 40, C = 12, O = 16)

Single correct option

What is the mass of 0.25 mole of calcium carbonate, CaCO3? (Atomic masses: Ca = 40, C = 12, O = 16)
  1. A. 100 g
  2. B. 12.5 g
  3. C. 25 g
  4. D. 40 g
Show answer and solution

Answer: (C) 25 g

Molar mass of CaCO3 = 40 + 12 + 3 x 16 = 100 g/mol. Mass of 0.25 mol = 0.25 x 100 = 25 g. The value 100 g is the mass of a full mole, and 12.5 g comes from dividing by 2 instead of multiplying by 0.25, while 40 g only counts calcium.
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Original question written in the NDA 2025 GAT pattern and checked twice for the correct answer. Not an official question paper. How we write and check questions · Corrections policy · Report a mistake