What Signs Show a Chemical Reaction has Occurred?

What Signs Show a Chemical Reaction has Occurred?
{Coughs}
Color Change
{Sneezes}
A change in smell indicates a chemical reaction
{Please}
Precipitate
To remember the signs of a chemical reaction use the phrase:
Please Excuse Coughs Sneezes and Burps
Leaves change color in autumn
Frying an egg
{Excuse}
Energy Change
A solid is formed when two liquids are mixed.
Two clears make a cloudy!
A reaction that gives off light or causes a temperature change
An unexpected color change indicates a chemical reaction
Smell
{Burps}
Bubbles
Bubbles, or the release of gas is an indicator of a chemical change
To Summarize...
Please =
Excuse =
Coughs =
Sneezes =
and
Burps =
Precipitate
Energy Change
Color Change
Smell Change
and
Bubbles
Chemical Vs. Physical Changes
Chemical Changes
Create a NEW substance!
Change what matter is made of
Generally can't be undone
Physical Changes
In general physical changes can be undone
Causes a change in appearance
(BUT NOT ALWAYS)!
Signs that a Physical Change has occurred include:
A change in Shape or Size
A change in the state of matter
(A Phase Change)
Evaporation
Condensation
Sublimation
Freezing
Melting