1. 8.500 moles of chlorine atoms contain 5.119 x 10^24 chlorine atoms. This can be calculated using Avogadro's number (6.022 x 10^23) multiplied by the number of moles (8.500).
2. The mass of 15.50 moles of oxygen is 496.48 g. This can be calculated by multiplying the number of moles (15.50) by the molar mass of oxygen (32.00 g/mol).
3. The number of moles of helium in 1.953 x 10^8 g of helium is 5,000 moles. This can be calculated by dividing the given mass (1.953 x 10^8 g) by the molar mass of helium (4.00 g/mol).
4. The number of atoms in 147.82 g of sulfur is 1.377 x 10^24 sulfur atoms. This can be calculated by dividing the given mass (147.82 g) by the molar mass of sulfur (32.06 g/mol), and then multiplying by Avogadro's number (6.022 x 10^23).
5. The molar mass of Co (cobalt) is 58.93 g/mol.
6. The formula mass of Ca3(PO4)2 (calcium phosphate) is 310.18 g/mol. This can be calculated by adding the atomic masses of all the atoms in the formula: (3 x atomic mass of calcium) + (2 x atomic mass of phosphorus) + (8 x atomic mass of oxygen).