Processing, please wait...
It was processed successfully!
It was processed successfully!
Login Create Free Account
Create Free Account

Reactants Definition

Reactants combine or rearrange in a chemical reaction to form products. For example, hydrogen and oxygen react to create water.

View Lesson on Chemical Reactions
Grades 6-8 VideoChemical Reactions player orange
Preview Only
Oops! It looks like your security settings are blocking this video 🙁

If you are on a school computer or network, ask your tech person to whitelist these URLs:
*.wistia.com, fast.wistia.com, fast.wistia.net, embedwistia-a.akamaihd.net

Sometimes a simple refresh solves this issue. If you need further help, contact us.


Chemical Reactions

Fun Facts

  • Reactants usually have different properties than products, even though the same number of atoms are present before and after a chemical reaction.
  • When a bath bomb goes through a chemical change, baking soda, citric acid, and water are the reactants.
  • The carbon dioxide gas that is formed when a bath bomb undergoes a chemical change is not one of the reactants.

Why Do We Need To Know About Reactants

Learning about reactants helps us understand how chemical reactions create new materials and medicines. These reactions are important for our health and everyday life.

Reactants are used outside of science labs. Chemical engineers and scientists use them to figure out tough problems, like making better rocket fuel for space trips or flexible solar panels for wearable gadgets. This tells us that knowing about reactants can lead to many job opportunities and has practical uses too.

Frequently Asked Questions

How is a physical change different from a chemical change?
In a physical change, no new substances are formed. In a chemical change, new substances are formed.
How do you know a chemical reaction has happened?
If a new substance is formed, it has different properties.
Give an example of a chemical change.
Steel wool burning, which causes the iron to combine with oxygen and form iron oxide.
Explore More Science Topics
We’ve sent you an email with instructions how to reset your password.
Choose Your Free Trial Period
3 Days

3 days to access to all of our teaching resources for free.

Continue to Lessons
30 Days

Get 30 days free by inviting other teachers to try it too.

Share with Teachers
Get 30 Days Free
By inviting 4 other teachers to try it too.
4 required

*only school emails accepted.

Skip, I will use a 3 day free trial

Thank You!

Enjoy your free 30 days trial