An object's chemical properties depends on how an object interacts with another substance. For example, whether an object burns or not (called its combustibility) is a chemical property. This is because, when an object burns, it combines with Oxygen.

So, to know about an object's tendency to burn, we need to know how it interacts with another substance (Oxygen in this case).
We can talk about the hardness of objects. For example, a stone is hard, whereas sponge is soft. Is the hardness of an object a physical or chemical property?
  • Physical
  • Chemical
  • Can't say