* Avogadro's Number: One mole of any substance contains 6.022 x 10^23 particles (atoms, molecules, etc.). This is known as Avogadro's number.

* Water Molecules: Since we have 1.00 mol of water (H2O), we have 6.022 x 10^23 water molecules.

Therefore, there are 6.022 x 10^23 water molecules in a block of ice containing 1.00 mol of H2O.