Question

Given: 4Na + O2 → 2Na2O In this chemical reaction, how many moles of Na2O will be produced if 2.90 moles of Na react completely? Express your answer to three significant figures.

There will be ???? moles of Na2O.

Answer 1

1.45 moles of Na2O produced. It is a 4:2 moles ratio between Na:Na2O which is the same as 2:1 ratio. So half the original moles of Na produced... which is 2.90/2 = 1.45

Answer 2

Answer: 1.45 moles of $Na_2O$

Explanation:

$4Na+O_2\rightarrow 2Na_2O$

According to the stoichiometry:

Given : Na react completely, thus sodium is a limiting reagent as it limits the formation of product. Oxygen will be excess reagent as it does not react completely.

4 moles of sodium produce 2 moles of $Na_2O$

Thus 2.90 moles of sodium produce =$\frac{2}{4}\times 2.90=1.45$ moles of $Na_2O$

Thus 1.45 moles of $Na_2O$ will be produced.