or a chemical reaction, the total mass of the substances does not change. Note: In the demonstrations and activities in this lesson, substances will be weighed before and after various processes have ...

Instead, the atoms rearrange themselves to form new chemicals. This is known as a chemical change. The other kind of change in chemistry is a physical change, which is when a substance changes ...

There are three core practical activities in the Chemical changes section: investigate the change in pH on adding powdered calcium hydroxide or calcium oxide to a fixed volume of dilute ...