Answer: 8 Moles of Oxygen
Explanation: The formula shows that there are (exactly) 4 oxygen atoms in each mole or formula unit. Therefore 4 * 2.00 = 8.
Depends on what the problems are, you are going to have to be a bit more specific, Young Padawan
A. K+, OH-
B. C6H5CO+, OH-
C. NH4+, Cl-
D. Mg++, 2 NO3-
Everything has 1 except for the Nitrate ion in D, which has 2