Question

How many total atoms are in 0.850 g of P₂O₅?

Answer 1

Given :

Mass of P2O5 = 0.850 g

Solution:

Obtain the molar mass of P2O5

Mol mass of P2O5 = 141.943 g /mol

Calculate moles of P2O5

            Formula : n = mass in gram / molar mass

Plug in mass and molar mass

                        n P2O5 = 0.850 g / 141.943 g per mol

                                    = 0.0060 mol

Use Avogadro’s number and find out number of molecules of P2O5

1 mol P2O5 molecules = 6.02 E 23 P2O5 molecules.

Calculate number of P2O5 molecules in 0.0060 mol

            Number of P2O5 molecule = 0.0060 x 6.02 E 23

                                                         = 3.6 E 21 P2O5 molecules.

Find out number of each atom in 1 molecule of P2O5

1 molecule P2O5 contains 2 atom P and 5 atom O ; There fore total atoms in 1 molecule of P2O5 would be 7

Calculate number of atoms in 3.6 E21 P2O5 molecules.

Number of atoms = 3.6 E 21 P2O5 molecule x 7 atm / 1 molcule P5O5

                              = 2.5235 E 22 atoms.

Total atoms = 2.52 E 22 atoms