Answer:
2NH₃(g) + 5F₂(g) → N₂F₄(g) + 6HF(g)
(a) mol of NH₃ required = 1.333 mol; mol of F₂ required = 3.333 mol
(b) mass of F₂ required = 142.5 g
(c) N₂F₄ produced = 10.38 g
Step-by-step explanation:
2NH₃(g) + 5F₂(g) → N₂F₄(g) + 6HF(g)
What is Stoichiometry?
In chemical equations, unless stated otherwise, the reactants and products will theoretically always remain in stoichiometric ratios.
The stoichiometry of a reaction is the relationship between the relative quantities of products and reactants, typically a ratio of whole integers.
Consider the following chemical reaction: aA + bB ⇒ cC + dD.
The stoichiometry of reactants to products in this reaction is the ratio of the coefficients of each species: a : b : c : d.
Converting between moles and mass:
To convert from mass to moles, divide the mass present by the molar mass, resulting in the number of moles.
Thence, the formula for moles: n = m/M, where n = number of moles, m = mass present, and M = molar mass. This formula can be easily rearranged to find mass present from molar mass and moles, or molar mass from mass and moles.
a. How many moles of each reactant are needed to produce 4.00 moles of HF?
In the given chemical equation, the stoichiometry of the reaction is
2 : 5 : 1 : 6. Therefore, for every 2 moles of NH₃, we require 5 moles of F₂, which will produce 1 mole of N₂F₄ and 6 moles of HF.
mol of NH₃ required = 1/3 × mol of HF = 1.333 mol
mol of F₂ required = 5/6 × mol of HF = 3.333 mol
b. How many grams of F₂ are required to react with 1.50 moles of NH₃?
Using stoichiometry again: mol of F₂ required = 5/2 × mol of NH₃
∴ F₂ required = 3.75 mol.
Then we can convert this to mass: m = nM = (3.75)(2×19.00) = 142.5 g
c. How many grams of N₂F₄ can be produced when 3.40 grams of NH₃ reacts?
Converting mass to moles: n = m/M = 3.40/(14.01+1.008×3) = 0.1996 mol
Using stoichiometry again: mol of N₂F₄ produced = 1/2 × mol of NH₃
∴ N₂F₄ produced = 0.0998 mol
converting moles to mass: m = nM = (0.0998)(14.01×2+19.00×4)
∴ N₂F₄ produced = 10.38 g