Chemical Properties

• Chemical Property– something that leads to a change

in composition of matter

• Flammability –– ability to burn when oxygen is

present–Can be a good and bad property

(lighter fluid SHOULD be flammable, Carpet is bad to be flammable)

–Solids, liquids or gases.

• Reactivity-– the ability to combine with another

substance easily–Oxygen reacts with most

substances•Causes rusting of metals, allows fire to burn

•Nitrogen is not very reactive and is often added to reduce the other element side effects

How to tell the difference

Physical and Chemical Changes

• Physical Change- – physical properties change, but the

substance is the same–Change in what you see but does

not produce a new substance•Painting a house, cutting hair, ironing shirt, melting water/boiling water

Some physical changes are reversible, some are not

• Reversible—freezing & melting water, braiding hair

• Non-reversible—slicing a tomato, peeling an orange

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...

Chemical Change• Chemical Change-

– when substances react to form one or more NEW substances

–Look for permanent change in color, gas bubbles, leftover solid

–Non-Reversible

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 permanently

• It forms a leftover solid

–Examples:• Silver ring that turns green• Rusting cars• Copper pennies turning green• Baking powder in cake – cake rises• Vinegar and baking soda• Adding vinegar to milk• Lighting a match• Explosion or burning of wood

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 change• Evaporates salt water?• Physical change

What kind of change is it if someone...

•Mixes vinegar and baking soda?

•Chemical change