A 3.5 g copper penny has a positive charge of 29 µC. What fraction of its electrons has it lost?

Try answering each of the following simpler questions which should lead you to the answer. If you get stuck, say where.


How many copper atoms in 3.5 grams? (Hint: 1 mole of copper weighs 63.546 grams. That's it's atomic weight).

How many electrons per copper atom?

What's the charge of 1 electron?

So how many electrons in 29 µC?

Finally, what's the percentage of the number of electrons in 29 µC out of the total number of electrons in the penny?