Solve Physics Question: 3.0g Copper Penny & 38uC Positive Charge

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To solve the physics question regarding a 3.0g copper penny with a positive charge of 38μC, the correct approach involves calculating the number of electrons corresponding to the charge and the total number of electrons in the penny. The charge of an electron is essential for determining how many electrons contribute to the 38μC charge. Additionally, knowing that there are approximately 29 electrons per copper atom helps in calculating the total number of electrons in the penny. Ultimately, the solution reveals that the fraction of lost electrons is 1/(3.5E9).
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Hi; Could somebody please help me with this question: A 3.0g copper penny has a postive charge of 38uC. What fraction of its electrons has it lost?
The method I tried was: (3g/63.55g) x 6.02E23 x A(what I'm solving for) = 38xE-6. Than I took my answer and divided it by 29. However this will not give me the correct answer, and the correct answer is 1/(3.5E9). Can somebody please help me. Thank you so much.
 
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Look at your units. You have a dimensionless number on the left side and coulombs on the right side. You need to factor in the charge on an electron.
 
Try a more systematic approach:

- How many electrons does it take to make up -38\mbox{\mu C} charge? (hint: use the electron charge)

- How many electrons are in 3.0g copper (when neutral)? (29 per copper atom)
 
Thanks...

Thanks guys, I figured this one out.
 

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