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