In white phosphorus, p atoms are joined into p4 molecules. white phosphorus is commonly supplied in chalk-like cylindrical form. its density is 1.823 g/cm3. for a cylinder of white phosphorus 7.00 cm long and 1.26 cm in diameter, determine the number of moles of p present and the total number of p4 atoms

Explanation:

It is known that volume of a cylinder is as follows.

              Volume of cylinder =

                                               =

                                               = 8.72

Therefore, mass of =

                                 =

                                 = 15.90 g

As, number of moles of a substance equals its mass divided by its molar mass.

Hence.     No. of moles of

                                                 =

                                                 = 0.1283 mol

According to moles concept, in one mole there are atoms.

Hence, in 0.1283 mol number of atoms of are calculated as follows.

             Molecules of

                                         = molecules

                                         = molecules

Therefore, atoms of P are calculated as follows.

                      molecules  

                         = atoms

Thus, we can conclude that total number of atoms are .