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Do Now #7A physical change occurs when a
substance changes form, but stays the same.
A chemical change occurs when a substance changes into a new, different substance.
1. In which Station Activities did you observe physical changes?
2. In which Station Activities did you observe chemical changes?
Physical vs. Chemical Physical Property
characteristics observed without changing the identity of the substance
Characteristics such as color, density, odor
Chemical Property
describes the ability of a substance to undergo changes in identity
Physical vs. Chemical
Lets think about the penny. What is the penny made out of?
Please tell me you didn’t say just copper!
Lets take a look at what the penny has done over the years.
Composition?
Why would the penny change (think of physical properties, as well as chemical properties?
B. Physical vs. Chemical Examples:
melting point
flammable
density
magnetic
tarnishes in
air
physical
chemical
physical
physical
chemical
Classify Each of the following as Physical or Chemical Properties
The boiling point of ethyl alcohol is 78°C.Physical property – describes inherent
characteristic of alcohol – boiling point
Diamond is very hard.Physical property – describes inherent
characteristic of diamond – hardness
Sugar ferments to form ethyl alcohol.Chemical property – describes behavior
of sugar – forming a new substance (ethyl alcohol)
Changes in MatterPhysical Changes are changes to matter
that do not result in a change of the fundamental components that make that substance (CHANGE IN CONDITION)State Changes – boiling, melting, condensing
Chemical Changes involve a change in the fundamental components of the substance (CHANGE IN MATERIAL)Produce a new substanceChemical reactionReactants Products
It’s a physical change if
It changes shape or size
It dissolves.
It changes phase (freezes, boils, evaporates, condenses)
•It’s a physical change if...
It’s a chemical change if….
It burns
Temperature changes without heating/cooling
It’s a chemical change if...
It bubbles (makes a gas)
It’s a chemical change if...
It changes color
It forms a precipitate
What kind of change is it if someone...
Tears up paper?
Physical change
Mixes salt and water?
Physical change
What kind of change is it if someone...
Burns paper?Chemical changeEvaporates salt water?Physical change
Table salt is stirred into water (left), forming a homogeneous mixture called a solution (right)
No chemical change occurs
when salt water is distilled
What kind of change is it if someone...
Mixes vinegar and baking soda?
Chemical change
Physical vs. Chemical
Examples:
rusting iron
dissolving in water
burning a log
melting ice
grinding spices
chemical
physical
chemical
physical
physical
Classify Each of the following as Physical or Chemical Changes
Iron is melted.Physical change – describes a state
change, but the material is still iron
Iron combines with oxygen to form rust.Chemical change – describes how iron
and oxygen react to make a new substance, rust
Sugar ferments to form ethyl alcohol.Chemical change – describes how sugar
forms a new substance (ethyl alcohol)
Properties of Matter
List of chemical changes possible.
Description by senses – shape, color, odor, etc.Measurable properties – density, boiling point, etc.
PROPERTIES
Old substance destroyed.New substance formed.
New form of old substance.No new substances formed.
CHANGE
CHEMICALPHYSICAL
