covert the quantities

Question

1.42×1027 P4O10 molecules to atoms..

7.743×1020 formula units PbCl4 to atoms

Answer 1

Use dimensional analysis:

each molecule of P₄O₁₀ contains 4 atoms of P and 10 atoms of O for a total of 14 atoms/molecule.

1.42x10²⁷ P₄O₁₀ molecules x 14 atoms/molecule = 1.99x10²⁸ atoms

Each formula unit of PbCl₄ contains 1 Pb atom and 4 Cl atoms for a total of 5 atoms/molecule

7.743x10²⁰ formula units x 5 atoms/formula unit = 3.872x10²¹ atoms