1. Physical Change
is the change of a subtance into a new one , example :
1 Buring paper
2 —Rice become rice
flour
—3 Apple decays
—4 Milk become yogurt
—5 asava become tape
2. Chemical Change
is the change of subtance that doesnt result new subtance , example :
1 —melting candle
2— ice moltens
3— making chair for
wood
4 glow lamp blazez
The changing of subtance to other subtance involves Chemical reaction , because of this chemical
changing is also known as chemical reaction
CHEMICAL REACTION
In a chemical
reaction :
—Reactant is : Starting material in a chemical reaction
Examples: H2 and O2 are reactants in the
reaction H2(g) + 1/2 O2(g) → H2O(l).
—prodact is : resulting substance
by a reaction
Exothermic ("outside
heating")
a process or reaction that releases energy from the system .
Examples : usually in the form of heat, but also in the
form of light (e.g. a spark, flame,
or explosion), electricity (e.g. a battery), or sound (e.g. burning
hydrogen).
Endhoternal : a chemical reaction
that absorbs / need heat
1.Chemical reaction
that produces precipitation
Around we there are
many met by chemical reaction who can
resulting sediment.
Attempt observes pan basic that
utilized to poach
water, what available substance that
stick at that pan
basic? That substance is
molded carbonate
compound while water that
containing lime is
heated.
Precipitation with
chemical reaction have so long
utilized for water
depurating process. Well water that
feculent effect gets
slime mingling can be cleared up by
alum increase. That
alum will tie-up partikelpartikel
slime so wadding and
finally
precipitate.
2 . Chemical reaction
that produces change color
Have you ever noticed
changing one
happening upon pruned
apple and is let
a few moments? That
fresh apple long time too long
on the turn as tan
colored. Discoloration
this points out that
chemical substance on apple has reacted
with oxygen in midair
3. Chemical reaction
that produce gas
In day-to-day life,
there are many we find
chemical reaction
that marked by formed its gas.
While are carbide
dash with water, will result
acetylene. This gas
generally been utilized for need
metal dialing with pengelasan. Besides gas
carbide can also be
utilized to hasten
brew numbers
4 Chemical reaction
that produce a change of temperature
A chemical reaction
that results energy
named by eksoterm's reaction. If that
energy as
heat, you can know it
by measures
its temperature
ascension. Burn reaction constitutes
example reacts eksoterm.
Upon you mereaksikan carbide with water,
you can feel
temperature ascension on wall
place glass reacts to
be done. Outgrow temperature ascension
can be measured by
thermometer
HOW TO WRITE REACTION EQUATION
1. cheking for balance
changing for balance has the same number of atoms of
each element on both sides of the
equation.
2 Chossing coefficient
in a chemical equation for tarnishing , the sulfur and the hydrogen atome are
already balanced . Putting a coefficient before
formulas that contain these atoms is not
necesarry at this time.
BALANCE CHEMICAL EQUATION
Step 1 : describe the reaction
in word , putting the reactants on the
left side and the product
on the right slide.
Step 2 : write a chemical
equation for the reaction using formulas and symbol Review how
to write formulas for compound
in section 11-4 . The formulas for element are
generally just their symbol . However as your read in chapter 12 some element
ordinarily exist as diatomic molecules .
Step 3 : check the equation
for atom balance .
Step 4 : choose coefficient
that balance the equation remember , never change subscripts of a
correct formula to
balance an equation .
TYPE OF CHEMICAL REACTION
1. synthesis reaction
In a synthesis reaction , two or more subtances combine to from
another subtances
The generalized formula for this reaction
type is a follows
2 Decomposition
reaction
in a decompotion reaction , one one subtance breakes down or decomposes , into two
or more simpler subtance.
3 Displacement reaction
a single displacement reaction occurs when one element
replaces another in a
compound
Factor the influence the speed of chemical reaction
—1 Concentration of
reactants
The concentration of
reactants plays an impor
tant role in chemical kinetics.
2 —Surface area of
reactants
In heterogeneous
reactions, the rate of reaction
depends upon the surface area of solid
reactant
—3 Temperature
The rate of reaction
increases with the rise of
temperature. It can
be explain by the fact that at
higher temperature, a
greater fraction of colliding
molecules posse the necessary energy of
activation.
4 —Presence of catalyst
A catalyst is a
substance, which controls the rate
of reaction without
itself undergoing a permanent
chemical change
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