Explanation:
magnesium and sodium because they are minerals and part of iron
Copper has 29 protons, when dealing with Cu^2+ all that means is it lost two electrons. so now the element has 29 protons and 27 electrons. Protons are positive and electrons are negative and neutrons are neutral. So say you had an element X^2- then you have gained two more electrons so the element has an overall negative charge. hope that helps
Answer:
The answer is "
".
Explanation:
calculating the moles in
Eqution:

Calculating the amount of
produced:

So, the amount of dihydrogen produced = 
Answer: It means that the energy is being stored or preserved to be used at a later time.
Your question was a little vague, so if this isn't the answer you were looking for, just let me know and I'll fix it.
Hope this helps! Good luck! :D