1) In the year 1618, England was experiencing a drought. Despite the shortage of water, cattle refused to drink from a certain pond in Epson Common. A man named Henry Wicker took some interest in this, and went over and drank a bit of the water himself. It tasted terribly bitter. He took some home and after boiling off the water he was left with Magnesium Sulfate crystals. This salt became known as "Epsom Salts" and soon after they were being used to treat constipation all over Europe. The three naturally occurring isotopes of magnesium are: magnesium-24(23.985 amu), magnesium-25(24.986 amu) and magnesium-26(26.983 amu). Their percent abundances in nature are 78.99%, 10.00% and 11.01% respectively. What is the average atomic mass of magnesium? 2) There are four naturally occurring isotopes of iron: iron-56 (91.754% at 55.935amu), iron-54 (5.845% at 53.940 amu), iron-57 (2.119% at 56.935 amu) and iron-58 (0.2830% at 57.933 amu). What is the average atomic mass of iron?