Question

assume that each atom in a copper wire contributes one free electron. estimate the number of free electrons in a copper wire having mass 6.4gm.

Answer 1

Molar mass of copper = 63.5 gm/mole

No. of moles of copper =$\frac{massofcopper}{molarmassofcopper}$

No. of moles of copper = $\frac{6.4gm}{63.5gm/mole}$ = 0.1 mole (approx.)

One mole = $6.022\times {10}^{23}atoms$
No. of atoms in 0.1 mole of copper = $0.1\times 6.022\times {10}^{23}atoms=6.022\times {10}^{22}atoms$
If each atom of copper wire contains one free electron . Then no. of free electrons in copper wire is $6.022\times {10}^{22}$