Answer : 135 grams of sodium has 5.869 moles.
Solution : Given,
Mass of sodium = 135 grams
Molar mass of sodium = 23 g/mole
Formula used :

Now put all the given values in this formula, we get

Therefore, the moles of sodium present in 135 grams of sodium is, 5.869 moles.
Because of making the equestion to be more stable and form the best compound according to it's reactant.
As the earth is in the form of a sphere, the angle of incidence of the sun's rays at the earth's surface increases from the equator towards the poles and therefore the amount of heat received on a GIVEN AREA diminishes in the same direction. Temperature is therefore normally hottest near the equator and coolest near the poles.
A reaction in which Oxygen (O₂) is produced from Mercury Oxide (HgO) would be a decomposition reaction.
2HgO → 2Hg + O₂
If 250g of O₂ is needed to be produced,
then the moles of oxygen needed to be produced = 250g ÷ 32 g/mol
= 7.8125 mol
Now, the mole ratio of Oxygen to Mercury Oxide is 1 : 2
∴ if the moles of oxygen = 7.8125 mol
then the moles of mercury oxide = 7.8125 mol × 2
= 15.625 mol
Thus the number moles of HgO needed to produce 250.0 g of O₂ is 15.625 mol