Question

what is the missing coefficient to make a balanced equation? ?k + ?o₂ → ?k₂o be sure the equation is balanced before entering the coefficients.

Explanation:

Step1: Balance oxygen atoms

On the right - hand side, there is 1 oxygen atom in $K_2O$. On the left - hand side, oxygen is in $O_2$. To balance oxygen, we need 2 moles of $K_2O$ so that the number of oxygen atoms on both sides is 2. So the equation becomes $K+O_2
ightarrow2K_2O$.

Step2: Balance potassium atoms

Now, in $2K_2O$, there are 4 potassium atoms. So we need 4 moles of $K$ on the left - hand side. The balanced equation is $4K + O_2
ightarrow2K_2O$.

Answer:

4, 1, 2