Question

Help me please :) asap

Answer 1

Answer : C - 1.02 x 10²³

Explanation ;

1 molecule of Al(NO₃)₃ has 3 N atoms.

Al(NO₃)₃ → Al + 3N + 9O

Moles (mol) = Mass (g) / Molar mass (g/mol)

Mass of Al(NO₃)₃ = 12 g

Molar mass of Al(NO₃)₃ = (27 + 14 x 3 + 16 x 9) g/mol

                                       = 213 g/mol

Mass of Al(NO₃)₃ = 12 g / 213 g/mol

                              = 0.0563 mol

The stoichiometric ratio between Al(NO₃)₃ compound and N atoms is 1 : 3.

Hence,

         the moles of N atoms = moles of Al(NO₃)₃ x 3

                                              = 0.0563 mol x 3

                                              = 0.1689 mol

According to the Avogadro constant,

              1 mol of substance = 6.02 x 10²³ particles

Hence, N atoms in the 12 g of Al(NO₃)₃ = 0.1689 mol x 6.02 x 10²³ mol⁻¹

                                                                   = 1.016778 x 10²³

                                                                   = 1.02 x 10²³