A copper penny has a mass of of 3gram. The atomic number of copper is 29 and the atomic mass is 63,5gram/mol.what is the total charge of all electrons in the penny?
If a penny were made entirely of copper, it would contain 3/63.5 = 0.04724 moles of copper atoms, which would amount to
0.04724 * 6.02*10^23 = 2.84*10^22 copper atoms. Each atom has 29 electrons. Multiply
29*2.84*10^22*(electron charge) for the final answer, in Coulombs.
Since 1983, pennies in the USA have been made of 97.5% zinc, not copper, to save money. The mass decreased from 3.1 g to 2.5 g. They still cost more than 1 cent to produce.
To calculate the total charge of all electrons in the penny, we need to determine the number of electrons in the penny and then calculate their total charge. Here's how you can do it:
1. Determine the number of moles of copper in the penny:
- Convert the mass of the penny to moles by dividing it by the molar mass of copper.
- The molar mass of copper is 63.5 grams/mol, as given in the question.
- Number of moles of copper = mass of penny / molar mass of copper.
- In this case, mass of penny = 3 grams.
So, number of moles of copper = 3 grams / 63.5 grams/mol.
2. Calculate the number of electrons in the penny:
- Since the atomic number of copper is 29, it means that a neutral copper atom has 29 electrons.
- The number of electrons in the penny can be calculated by multiplying the number of moles of copper by the Avogadro's number, which is approximately 6.02 x 10^23/mol.
- Number of electrons in the penny = number of moles of copper * Avogadro's number.
3. Calculate the total charge of all electrons:
- Each electron has a charge of -1.6 x 10^-19 Coulombs.
- Multiply the number of electrons in the penny by the charge of each electron to get the total charge of all electrons.
- Total charge of all electrons = number of electrons in the penny * charge of each electron.
By following these steps and plugging in the values, you can calculate the total charge of all electrons in the penny.