please help me with honors chem molarity question

Question

Ammonia will react with fluorine to produce dinitrogen tetrafluoride and hydrogen fluoride (used in production of aluminum, in uranium processing, and in frosting of light bulbs).

2 NH₃(g) + 5 F₂(g)  N₂F₄(g) + 6 HF(g)

How many moles of NH₃ are needed to react completely with 13.6 mol of F₂?

A. 6.80 mol

B. 34.0 mol    

C. 2.27 mol

D. 27.2 mol

E. 5.44 mol

Answer 1

From the balanced equation, made a conversion factor out of F2 and NH3 so that moles of NH3 is in the numerator

2 moles NH3 / 5 moles of F2 Now multiply the factor by the number of moles of F2 given.

2 moles NH3 / 5 moles F2 x 13.6 moles F2 = 5.44 moles NH3 required. Notice that moles of F2 cancel in the calculation.