One mole of calcium carbonate (CaCO3) is equal to 100.09 grams of the compound. This can be calculated using the molar mass of CaCO3, which is the sum of the atomic masses of calcium, carbon, and three oxygen atoms. The atomic masses of these elements are:

- Calcium (Ca): 40.078 grams per mole

- Carbon (C): 12.011 grams per mole

- Oxygen (O): 15.999 grams per mole

Therefore, the molar mass of CaCO3 is:

40.078 g/mol (for Ca) + 12.011 g/mol (for C) + 3 * 15.999 g/mol (for 3 O) = 100.09 g/mol

So, one mole of CaCO3 is equal to 100.09 grams of the compound.