Answer
The molar mass of ammonia is $17~g/mol$
Work Step by Step
A nitrogen atom consists of 7 protons and 7 neutrons.
A hydrogen atom consists of 1 proton.
A molecule of $NH_3$ consists of 10 protons and 7 neutrons.
The mass of one molecule of $NH_3$ is $17~u$
Since $~1~u~$ has a molar mass of $1~g/mol$, the molar mass of ammonia is $17~g/mol$
