Thank you for answering my previous questions!
I have another one now in regards to the following question...
An unknown potential difference exists between the inner and outer surfaces of the membrane of a cell. The inner surface is negative relative to the outer surface. If 1.7 x 10-20 J of work is needed to eject a positive Calcium ion (Ca2+) from the interior of the cell, what is the value of the potential difference?
I think that I should be able to use the formula where work is equal to the charge of the particle times its electric potential difference. The work is given and by using the charge of the calcium ion, the electric potential difference could easily be solved for. However, my question is, what would the charge of the calcium ion be? Do we need to consider it's electrons/protons? Since it's given that it charge is 2+, would I just assume that its 2X the charge of a proton?
Thanks in advance!
If someone can help, I'd really appreciate it!
You're welcome! I'm glad to help you with your question.
In this case, you are correct that you can use the formula for work, which is given by:
Work = charge × potential difference
The charge of the calcium ion (Ca2+) is indeed 2+. This means that it has a charge of +2. The 2+ charge indicates that it has lost two electrons, resulting in a positive charge.
To answer your question about whether you need to consider its electrons or protons, it's important to note that the charge of an atom or ion is determined by the number of protons and electrons. In a neutral calcium atom, the number of protons (positive charges) is equal to the number of electrons (negative charges). However, when calcium loses two electrons, it becomes a Ca2+ ion with a +2 charge.
Since the charge of an ion represents the number of electrons gained or lost, you don't need to consider the individual protons or electrons. You can simply note that the charge of a calcium ion is +2.
Therefore, in your equation, the charge of the calcium ion (Ca2+) would be +2. By rearranging the formula:
Potential difference = Work / charge
You can substitute the given values:
Potential difference = (1.7 x 10^(-20) J) / (+2)
which should give you the value of the potential difference.
I hope this clarifies your question! Let me know if you have any further queries.