Question

what is the missing coefficient to make a balanced equation? ? na + o2 → na2o be sure the equation is balanced before entering the coefficients

Explanation:

Step1: Balance oxygen atoms

We have 2 oxygen atoms in $O_2$ on the left - hand side and 1 oxygen atom in $Na_2O$ on the right - hand side. To balance the oxygen atoms, we put a 2 in front of $Na_2O$: $Na+O_2
ightarrow2Na_2O$.

Step2: Balance sodium atoms

Now, on the right - hand side, we have 4 sodium atoms in $2Na_2O$. So, we put a 4 in front of $Na$ on the left - hand side. The balanced equation is $4Na + O_2
ightarrow2Na_2O$.

Answer:

4