Electric Charge Video Lessons

Concept

# Problem: Pennies today are copper-covered zinc, but older pennies are 3.1 g of solid copper. What are the total positive charge and total negative charge in a solid copper penny that is electrically neutral? The density of copper is 8900 kg/m3.

###### FREE Expert Solution

The number of moles in the penny can be expressed as:

$\overline{){\mathbf{n}}{\mathbf{=}}\frac{\mathbf{M}}{\mathbf{A}}}$, where M is the mass of the penny and A is the atomic weight per mole of copper (63.5 g/mol).

We can now get the number of moles in the penny as:

n = 3.1/63.5 = 0.0488 mol

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###### Problem Details

Pennies today are copper-covered zinc, but older pennies are 3.1 g of solid copper. What are the total positive charge and total negative charge in a solid copper penny that is electrically neutral? The density of copper is 8900 kg/m3.