Question

In order to plate a steel part having a surface area of 200 inch square with a 0.005 in.-thick layer of nickel: how many atoms of nickel are required

Answer 1

The surface area is given
`200 inch^(2)` and thickness is 0.005 inch thus, volume will be:

`V=A* T=(200* 0.005)inch^(3)=1inch^(3)`

Converting
`inch^(3)` to
`cm^(3)`

`1 inch^(3)=16.38 cm^(3)`

The density of Nickel is
`8.908 g/cm^(3)` thus, mass will be:

`m=d* V=8.908 g/cm^(3)* 16.38 cm^(3)=146 g`

Now, molar mass of nickel is 58.7 g/mol thus, number of moles can be calculated as follows:

`n=(m)/(M)=(146 g)/(58.7 g/mol)=2.48 mol`

in 1 mole there are
`6.023* 10^(23) atoms` thus, number of atoms in 2.48 mol will be:

`N=2.48* 6.023* 10^(23)=1.5* 10^(24)`

Therefore, number of atoms of nickel required is
`1.5* 10^(24)`