Answer:
21.3 g of dinitrogen tetrafluoride are formed by this reaction
Step-by-step explanation:
First of all, we need to determine the reaction:
2NH₃ + 5F₂ → N₂F₄ + 6HF
2 moles of ammonia react with 5 moles of F₂ in order to make 1 mol of dinitrogen tetrafluoride and hydrogen fluoride
As we only have the ammonia's mass, then the fluorine gas is the excess reagent.
We convert ammonia's mass to moles → 7 g / 17g/mol = 0.411 moles
Ratio is 2:1. 2 moles of ammonia produce 1 mol of tetrafluoride
Therefore, 0.411 moles will produce (0.411 . 1) / 2 = 0.205 moles of tetrafluoride
Let's convert the mass to moles: 0.205 mol . 104.01 g / 1mol = 21.3 g