Find : (i) No.of moles in `10^(20)` atoms of `Cu`
(ii) Mass of `200_(8)^(16)O` atoms in amu
(iii) Mass of `100` atoms of `N` in gm
(iv) No.of molecules & atoms in `54 gmH_(2)O`
(v) No.of atoms in `88gmCO_(2)` .

Explanation

To solve the given problems step by step, we will follow the concepts of moles, mass, and Avogadro's number.

### (i) Number of moles in \(10^{20}\) atoms of Cu

1. **Formula**: The number of moles (n) can be calculated using the formula:
\[ n = \frac{\text{Number of atoms}}{N_A} \]
...