Question

Calculate the total +ve (or -ve) charge on 3.11gm copper penny
atm no. of cu - 29
atm. mass of cu - 63.5gm

Answer 1

3.11 gm Cu is equivalent to 3.11/63.5 moles =0.04876 moles
as 1 moles has 6.022×10^23 no. of Cu atoms
so, 0.04876 mole will have 6.022×10^23×0.04876 atoms =0.2949×10^23 atoms of Cu

so, no. of positive charge(proton)= 29×0.2949×10^23=8.553×10^23

thanks.