Question

___K+___B2O3 -> ___K2O+__B

Answer 1

The first step is to balance the number of oxygen atoms in the equation.

In the reactants, there are 3 atoms of oxygen, in the products, there is only one atom. To balance it, we have to assign 3 as the coefficient of K2O.

$K+B_2O_3\to3K_2O+B$

Now, we have to balance potassium, there is one atom of potassium in the reactants and 6 of them in the products. Assign 6 as the coefficient of K:

$6K+B_2O_3\to3K_2O+B$

Finally, balance boron. There are two atoms of boron in the reactants and only one of them in the product. Assign 2 as the coefficient of B:

$6K+B_2O_3\to3K_2O+2B$

And that is the balanced equation.