## Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (4th Edition)

The total positive charge is $+1.36\times 10^5~C$ The total negative charge is $-1.36\times 10^5~C$
The molar mass of copper is 63.5 g/mol. We can find the number of moles $N$ of copper in one penny. $N = \frac{3.1~g}{63.5~g/mol}$ $N = 0.04882~mol$ In one copper atom, there are 29 protons. We can find the total positive charge. $q = (0.04882~mol)(6.02\times 10^{23}~atoms/mol)(29)(+1.6\times 10^{-19}~C)$ $q = +1.36\times 10^5~C$ The total positive charge is $+1.36\times 10^5~C$. Since the penny is electrically neutral, the total negative charge is $-1.36\times 10^5~C$