Question

what is the excess reactant for the following balanced equation when 13 moles of ALF3 are mixed with 9 moles of O2

Answer 1

Answer:

AlF₃ is the excess reactant

Explanation:

We are given;

• 13 moles of AlF₃
• 9 moles of O₂

We are required to identify the excess reactant;

First; we write a balanced equation for the reaction between O₂ and AlF₃

• O₂ and AlF₃ reacts to form Al₂O₃ and F₂
• Therefore; the equation of the reaction is

    4AlF₃ + 3O₂ → 2Al₂O₃ + 6F₂

Second, determine the mole ratio of  AlF₃ to O₂

• From the equation 4 moles of AlF₃ reacts with 3 moles of O₂
• Therefore; the mole ratio of AlF₃ to O₂ is 4 : 3

Third; we determine the excess reactant.

• From the mole ration, 13 moles of AlF₃ will require 9.75 moles (13×3/4) of O₂ but only 9 moles of oxygen are available.

• On the other hand, 9 moles of oxygen would require 12 moles (9×4/3) AlF₃. But we have 13 moles of AlF₃, which means AlF₃ is in excess.

Therefore; Oxygen gas is the rate limiting reactant and AlF₃ is the excess reactant (1 mole excess).