Answer:
6.26 g of O2.
Step-by-step explanation:
We'll begin by writing the balanced equation for the reaction of sodium, Na and oxygen, O2 to produce sodium oxide, Na2O.
This is shown below:
4Na + O2 → 2Na2O
Next, we shall determine the masses of Na and O2 that reacted from the balanced equation.
This is illustrated below:
Molar mass of Na = 23 g/mol
Mass of Na from the balanced equation = 4 x 23 = 92 g
Molar mass of O2 = 16x2 = 32 g/mol
Mass of O2 from the balanced equation = 1 x 32 = 32 g.
From the balanced equation above,
92 g of Na reacted with 32 g of O2.
Finally, we shall determine the mass of O2 needed to react with 18 g of Na.
This can be obtain as follow:
From the balanced equation above,
92 g of Na reacted with 32 g of O2.
18 g of Na will react with = (18 x32)/92 = 6.26 g of O2.
Therefore, 6.26 g of O2 is needed for the reaction.