Written, Researched, and Compiled
ByStorm Roberts
Chemical Reaction Basics:
Chemical Reaction Basics
What is a chemical reaction?
A chemical reaction is the joining of 2 or more reactants (atoms) in
order to create a product (compound). Chemical reactions can also be
the separation of a product in order to produce the two reactants you
started with.
Chemical Reaction Basics
What parts of the Atom are effected by the chemical
reaction?
The part of the atom that is effected is the electron. These
particles either form bonds with electrons from the other
atoms or break their bonds with other atoms depending on
the type of chemical reaction.
Chemical Reaction Basics
How does the law of mass relate to chemical reactions?
This law states that matter can never be destroyed. This relates
because it shows that, during the chemical reaction process, no
atom disappears (or stops existing) it just joins with another atom.
These atoms still have the ability to be separated again in order to
prove that no matter was lost.
Chemical Reaction Basics
Signs of a Chemical
Reaction!!:
> The production of a
precipitate (a solid formed
during the mixing of two
liquids)
> A change in color
Chemical Reaction Basics
Signs of a Chemical
Reaction (cnt.)
> A formation of a gas (aka
fizzing, boiling, etc)
> An increase or decrease in
temperature that has noting to
do with outside factors.
Energy & Chemical Reactions
The role of energy in Chemical reactions is displayed
by the way energy enables the reaction. Energy is what
gets the two reactants to a state where the electrons
can interact and start the chemical reaction process.
Energy is like the fuel needed to burn in order to cause
a chemical reaction. The two main types of energy
used are potential
and kinetic energy.
Energy & Chemical Reactions:
Energy & Chemical Reactions
Potential Energy
> Potential energy is energy that
is “stored” in the atoms. This
energy has the potential to be
released when said atom
undergoes a chemical reaction
with another atom.
Kinetic Energy
> Kinetic energy is energy that is
“the energy of motion”. Kinetic
energy is energy something has
when it is motion. When that said
something makes contact with
something else, some of this energy
is transferred. Kinetic energy is the
energy that can set an chemical
reaction off in the first place.
Energy & Chemical Reactions
But what do the two types of energies have to do with
chemical reactions?
Well, kinetic energy is the force that starts the reaction. When the two
atoms come together the kinetic energy is shared between the two, and
then the potential energy that is stored is set off, and keeps the reaction
going. An example of this is a fire and a candle. The fire sets off the
candle and the fire on the wick continues to make the candle burn.
Energy & Chemical Reactions
Exothermic and Endothermic Reactions
Exothermic Reactions
An Exothermic reaction is a
reaction that puts out energy.
This energy can be displayed as
heat or smoke. An example of
this is fire.
Endothermic Reactions
An endothermic reaction is a
reaction in which energy is
absorbed. This can be
displayed by a drop in
temperature.
Energy & Chemical Reactions
Examples of an
Endothermic Reaction
Examples of an Exothermic
Reaction
> melting ice cubes
> melting solid salts
> evaporating water
>mixing concentrated acid with
water
>oxidation of metals
These can be classified as
endothermic reactions. More
scientific examples consist of
dissolving ammonia chloride
into water or mixing water and
ammonium nitrate.
Exothermic Reactions are
typically ones that give off heat.
Any reactions that result in
boiling liquids or a burning
flame can be classified as
Exothermic reactions.
Types of Chemical Reactions:
Types of Chemical Reactions
There are several types of
chemical reactions including:
> Synthesis
> Decomposition
> Combustion
> Single Replacement
> Double Replacement
KOH + H2SO4 ---> K2SO4 + H2O
FeS + HCl ---> FeCl2 + H2S
NaCl + H2SO4 ---> Na2SO4 + HCl
AgNO3 + NaCl ---> AgCl + NaNO3
Types of Chemical Reactions
Synthesis:
In a synthesis reaction, 2 simple substances combine to form a more
complex substance. Two or more reactants making one product is
another way to identify a synthesis reaction. An example of this is the
combination of a simple hydrogen atom and a simple oxygen makes the
complex substance of WATER!
(water)
(cartoon of synthesis)
Types of Chemical Reactions
Decomposition:
During decomposition, a complex substance breaks down into simpler
parts. Decomposition is the opposite type of reaction then synthesis.
Decomposition is basically where they take a compound and break it
down into the original atoms.
( breaking down of water into hydrogen and oxygen)
Types of Chemical Reactions
Combustion:
A reaction that always involves the molecule O2. Combustion is the
reaction that is always equated with burning… in fact, nothing can burn
without combustion. Combustion is always a type of exothermic reaction.
An example of combustion is the burning of wood.
(wood burning
illustrated example)
(formula for the combustion
of rubbing alcohol)
Types of Chemical Reactions
Single Replacement:
Single replacement is when
there are reactants in which
one is a compound and one
is a plain atom. When the
two reactants react, one
element of the compound
attaches to the single atom
and the left over atom is
alone. In the beginning there
are two reactants and in the
end there are two products.
(Cartoon example of single
Replacement)
(formula for the single replacement
that zinc forms with hydrochloric acid)
Types of Chemical Reactions
Double Replacement:
Double replacement is when the parts of two atoms switch “partners”
with each other to form two new compounds. Since there are 2 parts 2
each compound, it would be as if compound AB combined with
compound CD to make compound AD and CB.
(this is an example of how double replacement would look if it were to happen between
silver nitrate and sodium chloride. The two combined to make silver chloride and
sodium nitrate)
(This is a cartoon
demonstration)
Examples, Examples, Examples!
Examples, Examples, Examples!
An example of an endothermic reaction would be the breaking of a
cold pack, as displayed in class. This happens because the liquid and
solid particles interacted with each other and had a reaction in which
the temperature of the new product dropped from the beginning
temperature of the two reactants as individuals.
Examples, Examples, Examples!
An example of an exothermic reaction would be how aluminum reacts
with a mixture of water and CuCl2. The aluminum begins to almost
burn and rust, it seems and raises the temperature up. In our
experiment, the harmless mixture went from a harmless room
temperature to a scalding 110°F, which is a large difference of 30°.
Examples, Examples, Examples!
An example of a synthesis reaction would be the reaction between 4
hydrogen atoms and 2 oxygen atoms. In the end it went from the
chemical formula of 2H2 + O2  2H2O2 . This is an example of
synthesis because in the end the atoms joined together into a
compound.
Examples, Examples, Examples!
An example of decomposition is shown in the experiment where you heat
up sodium bicarbonate (2NaHCO3). You see when you heat this
powder up, the different reactants that are in the compound break up
into Na2CO3+H2O+CO2. In the end, this is demonstrated by the fact
that the water (H2O) is accumulated on the edge of the test tube, and
the Carbon Dioxide (CO2) puts out the flame used in the testing. This
shows that decomposition is the reaction that occurs.
Examples, Examples, Examples!
An Example of combustion is the lighting of a magnesium strip on fire.
You see, the strip bursts into flames that have intense heat and a bright
light. This is combustion because, any reaction putting off fire, is
combustion. And clearly, magnesium puts off a flame.
Examples, Examples, Examples!
An examples of single replacement is an examples we have looked at
already. This is the of how aluminum mixes with a CuCl2 solution. You
see in the reaction goes like this: 3CuCl2 + 2Al 2AlCl3 + 3Cu. This is
causes the aluminum to take on an odd, rusted color and the acid to
turn to a greenish color from its original blue.
Examples, Examples, Examples!
Finally, an examples of the last type of chemical reactions, double
replacement, is the mixing of Sodium Sulfate (Na2SO4) and Barium
Chloride (BaCl2 to create Barium Sulfate (BaSO4) and Sodium
Chloride (2NaCl). This is an example of double replacement because in
the reaction each reactant switched the second half
A Conclusion (finally!!!)
Ok, so, there are so many different types of factors
affecting reactions, From energy to quantities,
everything can change everything else. There are
different types of reactions and also different out
comes. Just remember there is always a way to identify
the reactions and the changes.
Sources (pictures)
Fireworks (slide 3) http://disneybear.com/wpcontent/uploads/2006/07/FIREWORKS_2_L%5B1%5D.JPG
How to identify a chemical reaction (slides 6-7 first 3 pictures)
http://www.harpercollege.edu/tmps/chm/100/dgodambe/thedisk/chemrxn/signs4.htm
Heat (slide 7 bottom picture) http://images.google.com/images?gbv=2&hl=en&q=heat
Explosion (slide 8) http://upload.wikimedia.org/wikipedia/commons/c/c7/Explosions.jpg
Billiards (slide 10) http://66.116.149.136/images/billiards.JPG
Ice Cube (slide 12)http://images.google.com/images?gbv=2&hl=en&q=ice+cubes
Campfire (slide 12) http://www.dracutforum.net/wpcontent/uploads/2007/08/campfire.jpg
Pictures and graphs for slides 16, 17, 19, 20
http://www.usoe.k12.ut.us/curr/science/sciber00/8th/matter/sciber/chemtype.htm
Combustion picture and graph(slide 18):
http://www.iun.edu/~cpanhd/C101webnotes/chemical%20reactions/combustion.html
Picture of cold pack (slide 22) : http://static.howstuffworks.com/gif/cold-pack.jpg
Sources (pictures cont.)
Picture of thermometer(slide 23):
http://images.google.com/images?gbv=2&hl=en&q=thermometer
Picture of baking soda (slide 24):
http://images.google.com/images?hl=en&q=baking+soda&gbv=2
Picture of test tube (slide 25): http://www.culturemediasupplies.com/TT9800C%20Test%20tube%20small2.jpg
Picture of magnesium(slide 26): http://www.culturemediasupplies.com/TT9800C%20Test%20tube%20small2.jpg
Picture of aluminum ball (slide 27):http://myscruffer.com/images/FoilBall.jpg
Sources (sites)
What happens during a chemical reaction:
http://wiki.answers.com/Q/What_happens_when_a_chemical_reaction_occurs
Definition of reactant: http://chemistry.about.com/library/glossary/bldef7550.htm
Definition of product: http://chemistry.about.com/library/glossary/bldef7050.htm
Law of Conservation of mass: http://dbhs.wvusd.k12.ca.us/webdocs/Thermochem/LawCons-Mass-Energy.html
How to tell there's been a chemical reaction:
http://dbhs.wvusd.k12.ca.us/webdocs/Thermochem/Law-Cons-Mass-Energy.html
Types of energy: http://www.fordhamprep.com/gcurran/sho/sho/lessons/lesson16.htm
Endothermic reactions: http://chemistry.about.com/od/lecturenotesl3/a/endorxns.htm
Exothermic reactions: http://chemistry.about.com/od/lecturenotesl3/a/endorxns.htm
Definitions of synthesis, decomposition, double replacement, and single replacement:
http://www.usoe.k12.ut.us/curr/science/sciber00/8th/matter/sciber/chemtype.htm
Definition of Combustion:
http://www.iun.edu/~cpanhd/C101webnotes/chemical%20reactions/combustion.html
Sources (Others)
All examples in the example section were provided by the experiments of
one Mr. Wildeboer, from his 9th grade honors integrated science class.
Documentation of these examples are provided in the form of a
worksheet on the types of reactions.
Thank you, Mr. W. for making this information accessible.