Is this chemical equation balanced?

No, it isn’t.

In order to balance this equation, you need to have the same amount of atoms of each element on both sides. (Law of conservation of mass)

So you’ve got 1 h2 and 1 o2 as the reactants and h2o as the product. So we need more oxygen for h2o to be balanced, and it becomes 2h2o. But then we need more hydrogen in the reactants for it to be balanced so h2 becomes 2h2. Therefore:

2h2+ 1o2—>2h2o