To determine how many molecules are present in 4NH₃ (ammonia), we need to understand what the notation means. The ‘4’ in front of NH₃ indicates the number of molecules of ammonia. Therefore, if you have 4NH₃, it simply means you have 4 molecules of ammonia.
Ammonia (NH₃) itself consists of one nitrogen atom (N) and three hydrogen atoms (H) per molecule. But since the question specifically asks how many molecules are present, the answer is straightforward: there are 4 molecules of NH₃.