Question

(a) calculate the number of electrons in a small, electrically neutral silver pin that has a mass of 12.0 g. silver has 47 electrons per atom, and its molar mass is 107.87 g/mol.

Answer 1

First calculate for number of moles:

moles Ag = 12 g / (107.87 g / mol)

moles Ag = 0.111 mol

Convert to atoms using Avogadros number:

atoms Ag = 0.111 mol * (6.022 x 10^23 atoms / mol)

atoms Ag = 6.7 x 10^22 atoms

There are 47 electrons per atom, therefore:

Number of electrons = (6.7 x 10^22 atoms) * (47 electrons / atom)

Number of electrons = 3.15 x 10^24 electrons