Two substances, x and y, are to be identified. substance x cannot be broken down by a chemical change. substance y can be broken down by a chemical change. what can be concluded about these substances?

We can conclude that substance x is an element and y is a compund.

For elements, it's the simplest substance and it cannot be further broken down into anything simpler by chemical methods. Examples include hydrogen oxygen etc.

But substance, they're 2 or more elements or compounds chemically combined together, they can be broken down with chemical methods such as using electricity (electrolysis) or applying heat.

Therefore, x is element and y is compound.