Question

For the following reaction, 24.8 grams of diphosphorus pentoxide are allowed to react with 13.2 grams of water . diphosphorus pentoxide(s) + water(l) phosphoric acid(aq) What is the maximum mass of phosphoric acid that can be formed? grams What is the FORMULA for the limiting reagent? What mass of the excess reagent remains after the reaction is complete? grams

Answer 1

Answer:

The maximum mass of phosphoric acid that can be formed is 34.2 g

The molecular formula of the limiting reagent is P₄O₁₀

The mass of the excess reagent (water) that remains after the reaction is complete is 3.76 g

Explanation:

Hi there!

Let´s write the balanced chemical equation:

P₄O₁₀ + 6 H₂O → 4 H₃PO₄

The molar masses of the reactants and the product are the following:

P₄O₁₀ = 284 g

H₂O = 16 g

H₃PO₄ = 98 g

The number of moles of the reactants we have are the following:

24.8 g P₄O₁₀ · 1 mol/ 284 g = 0.0873 mol P₄O₁₀

13.2 g H₂O · 1 mol/ 18 g = 0.733 mol H₂O

We know from the chemical equation that 1 mol of P₄O₁₀ reacts with 6 mol of H₂O, then, 0.0873 mol P₄O₁₀ will react with:

0.0873 mol P₄O₁₀ · 6 mol H₂O/ 1 mol P₄O₁₀ = 0.524 mol H₂O

Then, water is in excess because we have 0.733 mol and only 0.524 mol will react. Thus, the limiting reagent is P₄O₁₀

The number of moles of water that will remain after the reaction is complete is the following:

0.733 mol - 0.524 mol = 0.209 mol

Let´s convert that amount of water into mass units

0.209 mol · 18 g / mol = 3.76 g

3.76 g of water remains after the reaction is complete.

Assuming that the reaction has a yield of 100% since 1 mol of P₄O₁₀ produces 4 mol of phosphoric acid, 0.0873 mol P₄O₁₀ will produce

( 0.0873 mol P₄O₁₀ · 4 mol H₃PO₄/ mol P₄O₁₀ ) 0.349 mol phosphoric acid.

Then, the maximum mass of phosphoric acid that can be formed is the following:

0.349 mol H₃PO₄ · 98 g / 1 mol = 34.2 g