Question

How many copper atoms are in a pure copper statue with a mass of 129 kg?

Answer 1

Molar mass of Cu = 63.55 g/mol

mass of Cu = 129 Kg

= 129000.0 g [using conversion 1 Kg = 1000 g]

we have below equation to be used:

number of mol of Cu,

n = mass of Cu/molar mass of Cu

=(129000.0 g)/(63.55 g/mol)

= 2.03*10^3 mol

we have below equation to be used:

number of atoms = number of moles * Avogadro’s number

number of atoms = 2.03*10^3 * 6.022*10^23 atoms

number of atoms = 1.22*10^27 atoms

Answer: 1.22*10^27 atoms