To calculate the moles of ammonia (\(NH_3\)) produced from 12.0 moles of hydrogen (\(H_2\)), we need to consider the balanced chemical equation for the formation of ammonia:

$$N_2 + 3H_2 → 2NH_3$$

From the equation, we can see that 3 moles of hydrogen are required for every 2 moles of ammonia produced. Therefore, we can use stoichiometry to determine the moles of ammonia:

$$12.0 \text{ mol }H_2 \times \frac{2 \text{ mol }NH_3}{3 \text{ mol }H_2} = 8.0 \text{ mol }NH_3$$

Therefore, 12.0 moles of hydrogen will produce 8.0 moles of ammonia.