Mole Concept

Question

How many moles of oxygen atoms are present in 5.0 g of CaCO3? (Atomic masses: Ca=40, C=12, O=16)

RankGuru · Accepted Answer

1. **Calculate Molar Mass of $CaCO_3$**:
   - $Molar \ mass = 40 (Ca) + 12 (C) + 3 	imes 16 (O) = 100 \ g/mol$.
2. **Find Moles of $CaCO_3$**:
   - $Moles = \frac{Mass}{Molar \ mass} = \frac{5.0 \ g}{100 \ g/mol} = 0.050 \ mol$.
3. **Relate $CaCO_3$ to Oxygen Atoms**:
   - Each formula unit of $CaCO_3$ contains **3 atoms of Oxygen**.
   - Therefore, $1 \ mol$ of $CaCO_3$ contains $3 \ mol$ of Oxygen atoms.
4. **Calculate Total Moles of Oxygen**:
   - $Moles \ of \ O \ atoms = 3 	imes 0.050 \ mol = 0.15 \ mol$.
5. **Final Result**: The quantity is $0.15$ mol.

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