Unit 1 Matter Concept 2 Properties

Chemical Properties

• Chemical Properties:

properties that can only
be observed or
measured by changing
the chemical identity of
a substance.
– By observing it a new

substance is formed

– Ex. Toxicity, flammability,

combustibility,
radioactivity, etc.

Chemical Properties

• Combustibility: how easily a

substance will set on fire
– Ex. Burning charcoal

• Reactivity: how easily a

substance reacts, usually
with an acid or base
– Ex. Fluorine gas is highly

reactive and will spontaneously
ignite a concrete block at room
temperature

• Oxidation: how easily a

substance reacts with oxygen
– Ex. Iron reacts with oxygen and

moisture to create rust

A few you may not know about…

Physical and Chemical Changes

Matter can undergo both physical and chemical changes.

• Physical Change: a change in a substance that only

affects its physical properties
– Ex. Cutting, coloring, crushing, melting, boiling, etc.

• Chemical Change: a change in a substance that affects its chemical properties thus a chemical reaction occurs and a new substance is formed
– Ex. Burning, rusting, decomposing, etc.

• Chemical Reaction: process by which the atoms of one or more substances are rearranged to form different substances

Law of Conservation of

Matter

• Matter is neither

created or
destroyed during a
chemical change.
It only changes
forms.
– Mass cannot be “lost”,

even when a
chemical reaction
happens.

Evidence of a Chemical Change

Signs that a chemical change has occurred,
resulting in a chemical reaction include:

• Release of light
• Temperature change
• Odor change
• Sudden color change
• Gas given off
• Sudden appearance of a solid (called a

precipitate)