Properties & Changes Textbook Section 14.3

What’s A Property? A quality belonging to something In Chemistry: Characteristic A quality belonging to something In Chemistry: Usually tied to what phase the sample is in

Two Types of Properties: PHYSICAL Properties (def.) a change that can be observed or measured without changing what the sample is made of The LOOK or FEEL of something Used to IDENTIFY a sample

Two Types of Properties: PHYSICAL Properties Examples: Color, Malleability, Elasticity… What else?

Two Types of Properties: CHEMICAL Properties (def.) a property that tells you how or if a substance has the ability to react with others Ability to change one thing to something else Used to IDENTIFY a sample Ask Yourself: Has the sample changed??

Two Types of Properties: CHEMICAL Properties Is the sample changed?? YES!! Copper is reacting with carbon dioxide & water to create patina

Two Types of Properties: CHEMICAL Properties Examples: Flammability, Combustion Temps, Toxicity, Reactivity in Water…

Distinguishing Between The Two Aluminum is silvery-white. A: Physical Property B: Chemical Property

Distinguishing Between The Two Calcium can do this in water. A: Physical Property B: Chemical Property

Distinguishing Between The Two Oak wood has a density of 0.8 kg/m3 A: Physical Property B: Chemical Property

Two Types of Changes: PHYSICAL Changes (def.) a change that DOES NOT affect the chemical composition of a substance A change in a physical property or phase Easily reversible

Two Types of Changes: CHEMICAL Changes (def.) change in which one or more substances turn into different substances Atoms rearrange themselves Bonds between atoms are broken and new ones form

Two Types of Changes: CHEMICAL Changes Also called a CHEMICAL REACTION Signs Not easily reversible Formation of a new substance with its own properties

Signs of a CHEMICAL Change Formation of a gas - Bubbles Release/Absorption of heat Color Change (different than original)

Signs of a CHEMICAL Change Formation of a solid – Precipitate Light – Release of Energy

Distinguishing Between The Two Practice: Each circle is an atom. Different colored circles are different elements Connected circles are molecules.

Distinguishing Between The Two Gold being melted to form bars A: Physical Change B: Chemical Change

Distinguishing Between The Two Wood burning in a fireplace A: Physical Change B: Chemical Change

Distinguishing Between The Two Clay being sculpted A: Physical Change B: Chemical Change