2.3 Chemical Properties
How would you describe
these candles? Color,
hardness, and density
are physical properties
that you can use in the
description. You can also
say that the candles are
burning. The ability to
burn is not a physical
property. As a candle
burns, new substances
form.
2.3 Chemical Properties
Observing Chemical Properties
As a candle burns, its compounds combine with
oxygen in the air to form water and carbon dioxide.
A chemical property is any ability to produce a
change in the____________________of matter.
Flammability and____________are two examples of
chemical properties.
Chemical properties can be observed only when the
substances in a sample of matter are changing into
different______________________.
2.3 Chemical Properties
Observing Chemical Properties
Flammability
Materials that burn can be used as fuel. Flammability
is a material’s ability to burn in the presence of
_____________.
Reactivity
The property that describes how readily a substance
combines_______________with other substances is
reactivity.
2.3 Chemical Properties
Observing Chemical Properties
Rust forms when oxygen reacts with iron and water.
Rust is a brittle, reddish-brown compound. Because
iron is_______reactive, you would not choose iron to
make jewelry or coins.
Nitrogen has many uses that depend on its low
____________________.
Researchers in Japan pump
nitrogen gas into the steel
tanks that hold__________in
ships. The nitrogen displaces
the oxygen dissolved in the
water and prevents rusting.
2.3 Chemical Properties
Recognizing Chemical Changes
Three common types of evidence for a chemical change
are a change in color, the production of a gas, and the
formation of a precipitate.
The color change in a banana peel is caused by chemical
changes that are taking place in the_______of the banana.
A chemical change occurs when a substance reacts and
forms one or more ______________________________.
2.3 Chemical Properties
Recognizing Chemical Changes
A Change in Color
A change in color is a clue that a chemical change
has produced at least one new substance.
• A shiny silver bracelet that is exposed to air will _______.
• As a match burns, it_____________up and turns black.
• A new copper roof and an old copper roof have different
colors.
A new copper roof has a
_______________color.
The_______patina on an old
copper roof is a mixture of
copper compounds.
2.3 Chemical Properties
Recognizing Chemical Changes
Production of a Gas
When you mix vinegar with baking soda, bubbles of
carbon dioxide form immediately. A similar chemical
change happens when you use baking powder as an
ingredient in a cake recipe. Bubbles of ____________
expand and cause the cake to rise.
2.3 Chemical Properties
Recognizing Chemical Changes
Formation of a Precipitate
Any solid that forms and separates from a liquid
mixture is called a_____________________.
When an acid is added to milk, proteins in the milk
undergo a chemical change that causes them to stick
together in clumps and form a precipitate–cottage
cheese.
2.3 Chemical Properties
Is a Change Chemical or Physical?
Are different substances present after a change takes
place? If not, then the change is physical, not
chemical.
When matter undergoes a chemical change, the
composition of the matter _________________.
When matter undergoes a physical change, the
composition of the matter remains ______________.
2.3 Chemical Properties
Is a Change Chemical or Physical?
Even if you observe a color change, a gas, or a
precipitate, you______be sure that a chemical change
has taken place.
When an iron horseshoe is heated, its color changes
from gray to red, but the iron is still iron. That means
the change is ______________________________.