Question

1.4 moles of phosphours trichoride are present in a sample. How many atoms are there in the sample

Answer 1

Each molecule of PCl₃ has 4 atoms namely 3 chlorine atoms and 1 phosphorus atom.

Also, 1 mole of PCl₃ contains Avogadro number of molecules.

1 mole of PCl₃ contains 4 x Avogadro number of atoms

So, 1.4 moles of PCl₃ contains 1.4 x 4 x Avogadro number of atoms

→ 1.4 x 4 x 6.022 x 10²³

→ 5.6 x 6.022 x 10²³

→ 33.72 x 10²³

→ 3.372 x 10²⁴ atoms

Thus, 1.4 moles of PCl₃ contains 3.372 x 10²⁴ atoms.

Hope it helps!!