To calculate the number of molecules in 100 moles, we use Avogadro's number, which is approximately \(6.02 \times 10^{23}\) molecules/mole. Therefore, to find the total number of molecules in 100 moles, we can multiply Avogadro's number by 100:
\[ 100 , \text{moles} \times 6.02 \times 10^{23} , \text{molecules/mole} = 602 \times 10^{23} , \text{molecules} \]
Now, we can express \(602\) in scientific notation.
The number \(602\) can be written as \(6.02 \times 10^2\). Therefore:
\[ 602 \times 10^{23} = 6.02 \times 10^2 \times 10^{23} = 6.02 \times 10^{25} \]
Thus, the number of molecules in 100 moles in scientific notation is:
\[ \boxed{6.02 \times 10^{25}} \]