#### Answer

Molar mass of N$H_{4}$N$O_{3}$ is 80.05 g.

#### Work Step by Step

Step by step: Molar mass of N$H_{4}$N$O_{3}$ is equal the sum of:
2 x AM of N = 4 x 14.0067 = 28.013 g
4 x AM of H = 4 x 1.00794 = 4.032 g
3 x AM of O = 3 x 15.9994 = 47.998 g
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Molar mass N$H_{4}$N$O_{3}$ = 28.013 g+4.032 g+47.998 g
N$H_{4}$N$O_{3}$ = 80.043 g
The molar mass N$H_{4}$N$O_{3}$ is 80.043 g, or 80.05 g.