Question

How many moles of anion are in 3.262 kg of potassium phosphate?

How many moles of ions are in 3.262 kg of potassium phosphate?

Answer 1

Write down the ionization of potassium phosphate, K3PO4 as below.

K3PO4 -------> 3 K+ + PO43-

The atomic masses are

K: 39.098

P: 30.974

O: 15.999

The gram molar mass of K3PO4 = (3*39.098 + 1*30.974 + 4*15.999) g/mol = 212.264 g/mol.

Mole(s) of K3PO4 corresponding to 3.262 kg = (3.262 kg)/(212.64 g/mol) = [(3.262 kg)*(1000 g)/(1 kg)]/(212.264 g/mol) = 15.3676 mole ≈ 15.37 mole (correct to four sig. figs).

Again, as per the stoichiometric equation,

1 mole K3PO4 = 1 mole PO43-.

Therefore,

15.37 moles K3PO4 = 15.37 moles PO43-.

There are 15.37 moles of anions corresponding to 3.262 kg potassium phosphate (ans).

Again, as per the stoichiometric equation,

1 mole K3PO4 = 3 moles K+.

Therefore,

15.37 moles K3PO4 = (3*15.37) moles K+ = 46.11 moles K+.

Total number of moles of ions = (46.11 + 15.37) moles = 61.48 moles.

There are 61.48 moles of ions corresponding to 3.262 kg potassium phosphate (ans).