Calculate the mass of potassium hydroxide required to react with phosphorus oxide 5 mass 28

Calculate the mass of potassium hydroxide required to react with phosphorus oxide 5 mass 28, 4 to obtain potassium phosphate.

Given:

m (P2O5) = 28.4 g

To find:

m (KOH) -?

Solution:

6KOH + P2O5 = 2K3PO4 + 3H2O, – we solve the problem based on the composed reaction equation:

1) Find the amount of phosphorus oxide that has reacted:

n (P2O5) = m: M = 28.4 g: 142 g / mol = 0.2 mol

2) We compose a logical expression:

If 1 mol of P2O5 requires 6 mol of KOH,

then 0.2 mol P2O5 will require x mol KOH,

then x = 1.2 mol.

3) Find the mass of potassium hydroxide required for the reaction to proceed:

m (KOH) = n * M = 1.2 mol * 56 g / mol = 67.2 g.

Answer: m (KOH) = 67.2 g.