The discussion focuses on calculating the fraction of electrons lost from a 3.0-gram copper penny with a positive charge of 67 mC. The correct approach involves determining the number of atoms in the penny using the molar mass of copper (63.54 g/mol) and Avogadro's number (6.022 x 10^23). The calculations yield approximately 8.2 x 10^23 electrons in the penny, and the fraction of lost electrons is calculated as (4.2 x 10^14) / (8.2 x 10^23), resulting in 5.1 x 10^-10. This method is confirmed as correct by participants in the discussion.
PREREQUISITESStudents in chemistry, physics, or engineering fields, particularly those studying atomic structure and electric charge concepts.
gillyr2 said:Homework Statement
A 3.0-g copper penny has a positive charge of 67 mC.
What fraction of its electrons has it lost?
Homework Equations
I don't think I am donig this right. i need guidance
The Attempt at a Solution
i take 3.0 grams * 63.5amu * 6.022 * 10^23 * 29 (electrons) = 3.3*10 ^ 27
67 * 10^-6C / 1.6 * 10 ^ -19C = 4.2 * 10^14
3.3*10 ^ 27/4.2 * 10^14 = WRONG ANSWER. HELP!
gillyr2 said:ok. would this be correct?
3.0 grams / 63.5amu * 6.022 * 10^23 * 29 (electrons) = 8.2 *10^23
67 * 10^-6C / 1.6 * 10 ^ -19C = 4.2 * 10^14
(4.2 * 10^14)/(8.2 * 10^23) = 5.1*10^-10
Is this correct?