Physical
change
- is the change of substance that is temporary while the structure
doesn’t change, but the shape
changes.
- a physical change is reversible process and
doesn’t create a new matter
Chemical
change - is
the change of structure that is permanent and also the structure and the shape changes.
- a chemical change is irreversible
process and create a new matter
Some example about the matter change
!
Water heats, paper burns, ice melting, melting,
cooling, freezing, boiling, vaporizing, sublimating, condensing, burning, corroding,
iron covered with paint ,
rusty iron, vaporized gasoline , frozen water, rotten garbage, exploded firecrackers, burned
kerosene.
Chemical reaction
-
Can be identified based on
the change happening in the reaction
-
Some changes can be in the
form:
v Precipitation/sediment
v Color
changes
v Gas
production
v Temperature
changes
Chemical
reaction that produces precipitation
n Examples:
when limewater is blown, it will cause a reaction between the water with
carbondioxide, the result white calcium carbonate
Chemical reaction
that produces change of color
n Reaction
between cassava flour and tincture iodium, it will produce blue color
n The
color change when the cut apple exposed to the air for a while, its color into
brown
Chemical reaction that
produces gas
n Example
: when mix carbide with water, it will form acetylene that commonly used to
join metals in a welding process and to ripen some fruits.
Chemical reaction that
produces a change of temperature
n When
you mix carbid with water, you can feel the rising temperature on the wall of
the glass where the reaction takes place.
n All
reaction always involve energy.
n One
chemical eaction that produce energy is called exothermic.
n One
chemical eaction that needs energy is called endothermic,
Example : photosynthesis process.
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