Answer to Question #152895 in Chemistry for Arvin Shopon

Question

2. Phosphorus (V) oxide P4O10 is used to prepare phosphoric acid.

a) Write the reaction equation when solid phosphorus (V) oxide is prepared by burning solid phosphorus P4.

b) How much phosphorus (V) oxide can be produced when 1.33 g of phosphorus and 5.07 g of oxygen are available?

Answer 1

Solution:

a) The reaction equation when solid phosphorus (V) oxide is prepared by burning solid phosphorus P₄:

P₄(s) + 5O₂(g) → P₄O₁₀(s)

According to the equation: n(P₄) = n(O₂)/5 = n(P₄O₁₀)

b):

1) Moles of P₄ = Mass of P₄ / Molar mass of P₄

The molar mass of P₄ is 123.895 g mol^-1.

Hence,

Moles of P₄ = 1.33 g / 123.895 g mol^-1 = 0.0107 mol

n(P₄) = 0.0107 moles

2) Moles of O₂ = Mass of O₂ / Molar mass of O₂

The molar mass of O₂ is 15.999 g mol^-1.

Hence,

Moles of O₂ = 5.07 g / 15.999 g mol^-1 = 0.3169 mol

n(O₂) = 0.3169 moles

According to stoichiometry:

1 mol of P₄ reacts with 5 mol of O₂

Thus 0.0107 moles of phosphorus (P₄) reacts with:

(0.0107 mol P₄ × 5 mol O₂) / 1 mol P₄ = 0.0535 mol O₂.

However, initially there is 0.3169 moles of O₂ (according to the task).

Thus P₄ acts as limiting reagent and O₂ is excess reagent.

Therefore,

n(P₄O₁₀) = n(P₄) = 0.0107 mol (according to the equation).

The molar mass of P₄O₁₀ is 283.886 g mol^-1.

Mass of P₄O₁₀ = Moles of P₄O₁₀ × Molar mass of P₄O₁₀

Mass of P₄O₁₀ = 0.0107 mol × 283.886 g mol^-1 = 3.0376 g = 3.04 g

Mass of P₄O₁₀ is 3.04 grams.

Answer:

a) The balanced chemical equation: P₄(s) + 5O₂(g) → P₄O₁₀(s)

b) 3.04 grams of P₄O₁₀ (or 0.0107 mol P₄O₁₀) can be produced.