Question

Calculate the total positive or negative charge on a $3.11g$ copper penny. Given Avogadro number $=6.02\times {10}^{23}$, atomic number of copper $=29$ and atomic mass of copper $=63.5$

• A. $3.37\times {10}^{5}C$
• B. $2.37\times {10}^{5}C$
• C. $1.37\times {10}^{5}C$
• D. $0.37\times {10}^{5}C$

Answer 1

The correct option is C $1.37\times {10}^{5}C$

The number of atoms in given copper: $\frac{6.023\times {10}^{23}\times 3.11}{63.5}$
Given, atomic number of copper $=29$
So, each atom contains 29 protons and 29 electrons.
So, the positive or negative charge on it $=\pm \frac{(6.023\times {10}^{23}\times 3.11)\times 29\times 1.6\times {10}^{-19}}{63.5}$

$=\pm 1.37\times {10}^{5}C$