Properties of Matter: Chemical Properties

Slide 168 / 177

Chemical Properties

We have spent some time discussing physical properties.

A chemical property is a characteristic of a pure substance that

describes its ability to change into a new substance.

Chemical properties can only be observed if the matter undergoes a

chemical reaction resulting in chemical change.

A chemical reaction between a metal and gas makes table salt.

Slide 169 / 177

Some chemical properties include flammability (or the ability
to burn), the ability to rust, corrosion (or breaking down) and

reactivity (or the ability to bond with other substances).

Matches ignite when you strike them because of a mixture of two

substances:

phosphorus and potassium chlorate.

These substances are highly flammable, but you would not be

able to tell until you lit them on fire!

Examples of Chemical Properties

Slide 170 / 177

A banana ripens and turns brown as a result of chemical

reactions, therefore, ripening is a chemical change.

Examples of Chemical Properties

This one is trickier, so it's helpful to think about the properites of a
banana before and after ripening. Fill in the characteristics below:

Before a banana ripens:
color:

texture:

taste:

After a banana ripens:
color:

texture:

taste:

Slide 171 / 177

Reactivity is the ease and speed with which an element is able to

combine or react with another element.

Elements in Groups 1 and 7 are very reactive and elements in Group 8

will hardly ever react.

Reactivity of Elements

Slide 172 / 177

Physical vs Chemical Properties

Physical Properties

Chemical Properties

sodium metal

chlorine gas

table salt

shiny, soft

very reactive

very stable
(does not react
with other
substances)

very reactive

Slide 177 / 177