The molar mass of copper is 63.5g/mol, and the density is 8.9 * 10 ^ 3kg / m ^ 3, It is estimated that the free electron number density of the copper dollar table is 4*10^28m^-3 I don't know how to get the answer

The molar mass of copper is 63.5g/mol, and the density is 8.9 * 10 ^ 3kg / m ^ 3, It is estimated that the free electron number density of the copper dollar table is 4*10^28m^-3 I don't know how to get the answer

The molar number of copper in 1m & sup3; is 8.9 * 10 ^ 3 * 10 ^ 3 / 63.5 = 140157.5mol
1mol copper contains Na = 6.022 * 10 ^ 23 copper atoms
So the number of free electrons in 1m & sup3; copper is 140157.5 * 6.022 * 10 ^ 23 = 8.4 * 10 ^ 28 / M & sup3;

The density of copper is 8900 kg / M and the molar mass of copper is 0.064 kg / mol

The volume of one mole of copper is v
V = 0.064/8900 = 0.00000719 m3 / mol = 7.19 cm3 / mol, substituting into the following formula
Spherical volume: v = 4 / 3 π R ^ 3
R ^ 3 = 1.71735669
d=2R
I'm sorry that I don't have a calculator in my hand. I can't use the computer to open the root. Please open it by yourself, but the calculation steps are very clear. I hope I can help you!