Question

How many atoms of gold (Au,196.97 g/mol) are in a gold nugget with a mass of 4.259?

Answer 1

Mass of gold nugget = 4.259 g

Calculating the moles of gold from mass and molar mass:

`4.259 g Au * (1 mol Au)/(196.97 g Au) = 0.0216 mol Au`

Calculating the atoms of Au:

`0.0216 mol Au * (6.022 * 10^(23) atoms Au)/(1 mol Au) = 1.3*10^(22) atoms Au`

Therefore,
`1.3 * 10^(22) atoms Au` are present in a gold nugget with a mass of 4.259 g.