Hydrazine (N_2H_4) decomposes to produce N_2 and NH_3. How many molecules of NH_3 will be formed if 90 molecules of N_2H_4 decompose into N_2 and NH_3?

Question

Hydrazine () decomposes to produce  and . How many molecules of  will be formed if 90 molecules of  decompose into  and ?

Answer 1

Just balance the reaction: 3 N₂H₄ --> N₂ + 4 NH₃. Now you can see that every 3 molecules of N₂H₄ produce 4 molecules of NH₃. For 90 molecules of N₂H₄ we scale up these numbers by a factor of 90/3 = 30. Therefore 4•30 = 120 molecules of NH₃ are formed.