So chemical changes. Chemical changes are changes in the chemical composition that creates a new chemical bond or bonds and product or products. So basically a chemical change changes the identity of your original substance.
Now some common types of chemical changes involved the rusting of metals. So the example that we had up above of iron rusting or old cars rusting is a prime example of a chemical change. The metal is transformed into a metal oxide by reacting with the oxygen in the air.
Next we have the burning of materials. So if you're burning, if you are baking, if you are cooking, you're doing. You're breaking down old bonds and creating new connections, thereby changing the identity of your original substance.
Next, we have the metabolism of food. So when you're eating, food goes to your digestive tract, your body absorbs nutrients. It becomes something completely different.
Next, chemical reactions. Chemical reactions involve our original substance undergoing some new chemical changes to create chemical bonds. And then finally the last two we can visually see. And that is when we have a color change. A substance might be clear and then it changes to blue or a color that we can see, or an odor change. Something might smell great and then it undergoes a chemical reaction and it becomes horrible in terms of smell. Or it could smell really bad and it does a chemical change and start smelling OK or lose its smell altogether.
Now remember, a chemical change is basically us changing the identity of a substance by changing its chemical bonds and connections.