Question

If you have 15.0 g of Na, how many grams of O2 are required for the reactionSodium reacts with oxygen to produce sodium oxide.4Na(s)+O2(g)→2Na2O(s)

Answer 1

`4Na_((s))+O_2\rightarrow2Na_2O_((s))`

Firstly we convert the mass of Na to moles of Na:

`\begin{gathered} _nNa_((s))=\frac{mass}{molar\text{ }mass} \\ _nNa_((s))=\frac{15.0g}{14\text{ }gmol^(-1)} \\ _nNa_((s))=1.07\text{ }mole \end{gathered}`

Based on the mole ratio 4 moles of Na reacts with 1 mole of O2. Therefore 1.07 mole of Na would react with x mole of oxygen gas. We determine x by:

`\begin{gathered} _nO_(2(g))=1.07\text{ }mole/4 \\ _nO_(2(g))=0.27\text{ }mole \end{gathered}`

We will now convert 0.27mol of oxygen gas to mass of oxygen gas:

`\begin{gathered} mass=mole* molar\text{ }mass \\ mass=0.27*32\text{ }gmol^(-1) \\ mass=8.64g \end{gathered}`

Mass of O2 is 8.64g