How many moles of magnesium is 2.77 x 10^24 atoms of magnesium?

4.6 moles.

Explanation:

To find the amount of moles of Magnesium, you will need to use Avogadro's number to convert between the two units.

2.77×10^24 moles Mg * (1 mol Mg)/(6.02*10^23)) ≈ 0.46×10^1 moles which equals 4.6 moles.

2h2o2--> 2h2o + o2

this reaction is of the spontaneous decomposition of hydrogen peroxide down into water and oxygen.

add 2 molecules of hydrogen peroxide and 2 molecules of water. since oxygen is naturally diatomic, the total number of atoms of each element is now the same on both sides of the equation so it is balanced.

this may not be entirely correct but let me know.