Key Idea.
Section 1
Creating Something New
How do we remove invisible pollutants from water? We can use a chemical reaction.
A chemical reaction happens when two or more substances mix and change into something entirely new. The original ingredients rearrange their atoms to form a new substance. This new material has a completely different identity from the starting materials.
Section 2
Looking for Evidence
How can you tell if a chemical reaction happened? You have to act like a detective and look for evidence.
Signs of a reaction include:
These clues tell you that a new substance has formed.
Section 3
Changing Properties
The most important part of a chemical reaction is that the properties change.
Imagine a pollutant that is poisonous and liquid. If we react it with a cleaner, it might turn into a safe, solid powder. The new substance (the powder) has different properties than the old substance (the poison). This change makes it possible to separate the bad stuff from the water.
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Section 1
Creating Something New
How do we remove invisible pollutants from water? We can use a chemical reaction.
A chemical reaction happens when two or more substances mix and change into something entirely new. The original ingredients rearrange their atoms to form a new substance. This new material has a completely different identity from the starting materials.
Section 2
Looking for Evidence
How can you tell if a chemical reaction happened? You have to act like a detective and look for evidence.
Signs of a reaction include:
These clues tell you that a new substance has formed.
Section 3
Changing Properties
The most important part of a chemical reaction is that the properties change.
Imagine a pollutant that is poisonous and liquid. If we react it with a cleaner, it might turn into a safe, solid powder. The new substance (the powder) has different properties than the old substance (the poison). This change makes it possible to separate the bad stuff from the water.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter