Explanation:
As it is given that solubility of water in diethyl ether is 1.468 %. This means that in 100 ml saturated solution water present is 1.468 ml.
Hence, amount of diethyl ether present will be calculated as follows.
(100ml - 1.468 ml)
= 98.532 ml
So, it means that 98.532 ml of diethyl ether can dissolve 1.468 ml of water.
Hence, 23 ml of diethyl ether can dissolve the amount of water will be calculated as follows.
Amount of water = 
= 0.3427 ml
Now, when magnesium dissolves in water then the reaction will be as follows.

Molar mass of Mg = 24.305 g
Molar mass of
= 18 g
Therefore, amount of magnesium present in 0.3427 ml of water is calculated as follows.
Amount of Mg =
= 0.462 g
1 mole of any substance contains Avogadro's number.
So, 1 mole of O2= 6.023x10^23 molecules
3 mole of O2= 6.023x10^23x3 molecules
= 1.8069x10^24 molecules
Each molecule of Oxygen has 2 atoms.
therefore,
1.8069x10^24 molecules= 1.8069x10^24 x 2 atoms
= 3.6138x10^24 atoms.
Galactic is referring to the galaxy and cosmos! :)
Here you go:
Continent Polar - Cold and Dry
Maritime Polar - Cold and Humid
Arctic - Extremely Cold and Dry
Maritime Tropical- Warm and Humid
Hope this helps:)
1 mol of formic acid is correct. There are two oxygen atoms in formic acid, compared to just one for the other molecules.