The reaction of fluorine with ammonia produces dinitrogen tetrafluoride and hydrogen fluoride.
5 f2(
g. + 2 nh3(
g. n2f4(
g. + 6 hf(
g. (
a. if you have 73.7 g nh3, how many grams of f2 are required for complete reaction?

b. how many grams of nh3, are required to produce 5.25 g hf?
(
c. how many grams of n2f4 can be produced from 269 g f2?

5F2 + 2NH3 --> N2F4 + 6HF 
60.1g NH3 / 17g/mole = 3.54moles NH3 
3.54moles NH3 x (5 F2 / 2NH3) x 38g/mole = 335.85g required 

5.25g HF / 20g/mole = 0.262moles HF 
0.262moles HF x (2NH3 / 6HF) x 17g/mole = 1.49g required 

209g / 38g/mole = 5.5moles F2 
5.5moles F2 (1 N2F4 / 5F2) x 66g/mole = 72.6g produced 

Li3N + 3H2O --> NH3 + 3LiOH 
(37.7g / 34.7g/mole) x (3H2O / 1 Li3N) x 18g/mole = 58.67g required 

1.08moles Li3N (1NH3 / 1Li3N) x 6.022x10^23molecules/mole = 6.54x10^23 molecules 

10.3L at STP: 10.3L / 22.4L/mole = 0.46moles NH3 produced 
0.46moles NH3 x (1Li3N / 1NH3) x 34.7g/mole = 15.96g