A 54.8 g ball of copper has a net charge of 2.5 µC. What fraction of the copper's electrons have been removed? (Each copper atom has 29 protons, and copper has an atomic mass of 63.5.)
To determine the fraction of copper's electrons that have been removed, we need to calculate the number of electrons initially present in the copper ball and compare it to the number of electrons remaining after removal.
Here's how you can calculate it step by step:
1. Calculate the number of moles of copper in the ball using the atomic mass of copper (63.5 g/mol):
moles of copper = mass of copper / atomic mass of copper
= 54.8 g / 63.5 g/mol
2. Calculate the total number of copper atoms in the ball using Avogadro's number (6.022 x 10^23 atoms/mol):
number of copper atoms = moles of copper x Avogadro's number
3. Find the total number of electrons initially present in the copper ball by multiplying the number of copper atoms by the number of electrons per copper atom. Since each copper atom has 29 protons (which are positively charged) in its nucleus, it also has 29 electrons (which are negatively charged) to balance the charge:
total electrons initially present = number of copper atoms x number of electrons per copper atom
= number of copper atoms x 29
4. Calculate the number of electrons removed by subtracting the net charge from the total electrons initially present:
number of electrons removed = total electrons initially present - net charge
5. Finally, calculate the fraction of electrons removed by dividing the number of electrons removed by the total electrons initially present:
fraction of electrons removed = number of electrons removed / total electrons initially present
Now you have all the steps to find the answer. Just plug in the values and perform the calculations!