Answer :
Final answer:
To calculate the number of moles of CaCO3 in a 39.4 g sample, you divide the sample's mass by the molar mass of CaCO3 (100.09 g/mol) to get approximately 0.394 moles.
Explanation:
To calculate the number of moles of CaCO3 in a 39.4 g sample, you need to use the molar mass of CaCO3. The molar mass of a compound is the sum of the masses of all the atoms in one mole of that compound.
The molar mass of calcium carbonate (CaCO3):
- Calcium (Ca) has an atomic mass of approximately 40.08 g/mol.
- Carbon (C) has an atomic mass of approximately 12.01 g/mol.
- Oxygen (O) has an atomic mass of approximately 16.00 g/mol, and there are three oxygen atoms.
So, the molar mass of CaCO3 is: 40.08 g (for Ca) + 12.01 g (for C) + 3 * 16.00 g (for O) = 100.09 g/mol.
Now, to find the moles of CaCO3 in the sample:
Moles of CaCO3 = mass of CaCO3 / molar mass of CaCO3 = 39.4 g / 100.09 g/mol ≈ 0.394 moles.