Chemical and Physical

Reactions

Physical Properties: characteristics of matter that can be observed without changing it to another substance.

Examples: _________ (mass/volume) ________ (can pulled into wires)

__________ (how easy it breaks) __________ (how stretchy)

_____________ (lets light through)

(Phase change)

Density Ductility

Brittleness Elasticity

Transparency

Boiling / freezing points

Physical ChangesIn a physical change, the substances are not altered chemically. No new products are formed. Chemical bonds are not broken in a physical change.

Usually Reversible

Examples Mixtures

Change shape

Phase changes

Make Kool-aid or lemonade

Ice to water to steamIce cream melts

Cutting (paper, trees, etc) Break Glass

Physical Change

• Physical changes might be caused by:– Grinding– Cutting– Crushing– Bending– Breaking– Heating/cooling

• (change in phase)– squishing

Physical Change

• Evidence that a physical change has occurred might include:– Change in shape– Change in form– Change in size– Change in phase (This is

always a physical change!)

Physical changes are usually reversible

Physical change• What could you do to

these items to cause a physical change to occur?

Chemical Properties Characteristics of matter that describe its ability to change into a new substance

Examples: _________________________ (ability to burn) ___________________(the ability to react with oxygen, which causes apple slices to turn brown and iron to rust) _________________________________(reacts to form new substance)

flammability

Ability to rustOxidation

Reactivity with acid

A change in matter that results in one or more new substances. You change what it is.

Chemical in the original substance combines with another chemical to create a new substance

Chemical Changes

Evidence of Chemical Reactions or Change

https://www.youtube.com/watch?v=cZMkqagL8Ps (2:52) Evidence of a Chemical Reactions

Evidence of Chemical Change

• New ________appears• Bubbbles or ________• Precipitate forms (____

material)

• _____ is produced• ______ is produced• ______ is given off

• Difficult or impossible to __________

colorfizzing

solid

reverse

HeatLightSound