Now, we need to convert moles to grams.
When we look at the periodic table, we see that there are 58.7 grams per mole
of Nickel (look at atomic weight). Now we just need to multiply the atomic
weight (grams per mole) by the amount of
moles we have (1.25 *10^-8)

Please let me know if you need any clarification. I'm always happy to answer your questions.

Jun 5th, 2015

For the answer 7.3 * 10 ^ -7, the units are grams of nickel. Sorry for not putting the units in the original :p . Let me know if you have any questions!