chemical reactions applied chemistry. chemical reaction chemical reaction – the type of reaction...
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Chemical Chemical ReactionsReactions
Applied ChemistryApplied Chemistry
Chemical ReactionChemical ReactionChemical reactionChemical reaction – The type of – The type of
reaction in which the properties of the reaction in which the properties of the reactantsreactants are different from the are different from the productsproducts..
Chemical ChangeChemical Change – A change that – A change that produces new substances with new produces new substances with new propertiesproperties and and compositionscompositions..PhysicalPhysical changes do changes do NOTNOT change the change the
identityidentity of a substance. of a substance. NuclearNuclear changes involve changes to the changes involve changes to the
nucleusnucleus. Ex) fission and fusion. Ex) fission and fusion
Signs of a chemical Signs of a chemical changechange
Change in Change in colorcolor
Formation of a Formation of a precipitateprecipitate (cloudiness, (cloudiness,
solid formed from 2 solutions)solid formed from 2 solutions)
Production of a Production of a gasgas (bubbles; fizzing) (bubbles; fizzing)
Increase or decrease in Increase or decrease in temperaturetemperature
Change or production of an Change or production of an odorodor
Chemical EquationsChemical Equations A description of a chemical reaction A description of a chemical reaction
using using symbolssymbols instead of instead of wordswords..
Parts of a Chemical Equation: Parts of a Chemical Equation: A.A. ReactantsReactants
B.B. ProductsProducts
C.C. ArrowArrow
D.D. Plus SignPlus Sign
Parts of Chemical EquationParts of Chemical EquationA. ReactantsA. Reactants
CHCH44 + O + O22 H H22O + COO + CO22
reactantsreactants productsproducts
Written on the Written on the leftleft side of the arrow side of the arrow
StartingStarting material in a chemical material in a chemical reactionreaction
Parts of Chemical EquationParts of Chemical EquationB. ProductsB. Products
CHCH44 + O + O22 HH22O + COO + CO22
reactantsreactants productsproducts
Written on the Written on the rightright side of the arrow. side of the arrow.
Newly formed substances that are Newly formed substances that are producedproduced in a chemical reaction. in a chemical reaction.
Properties are Properties are differentdifferent than those of the than those of the reactants.reactants.
Parts of Chemical EquationParts of Chemical EquationC. ArrowC. Arrow
CHCH44 + O + O22 H H22O + COO + CO22
reactantsreactants productsproducts
YieldYield sign sign
Means Means yields or producesyields or produces
Separates the Separates the reactantsreactants from the from the productsproducts..
Parts of Chemical EquationParts of Chemical EquationD. Plus signD. Plus sign
CHCH44 ++ O O22 H H22O O ++ COCO22
reactantsreactants productsproducts
Used to Used to separateseparate reactants and to reactants and to separateseparate products products
Symbols for Symbols for statesstates
HH2 2 (g)(g) + O + O2 2 (g)(g) H H22O O (l)(l)
KIKI(aq)(aq) + Pb(NO + Pb(NO33))2 2 (aq)(aq) PbI PbI22(s) (s) + KNO+ KNO33(aq)(aq)
Physical states of the reactants and products are in Physical states of the reactants and products are in parenthesis beside the formula. parenthesis beside the formula.
g: g: gasgas
l:l: liquidliquid
s:s: solidsolid
aq: aq: aqueousaqueous (dissolved in (dissolved in waterwater))
Example ReactionExample ReactionHH2 (g)2 (g) + Cl + Cl2 (g)2 (g) → HCl → HCl (g)(g)
What are the reactants? What are the reactants?
What are the products? What are the products?
What is the physical state of all What is the physical state of all
the substances? the substances?
H2 and Cl2
HCl
gas
CatalystsCatalysts CatalystsCatalysts are sometimes added to are sometimes added to
reactants to help reactants to help speed upspeed up a a chemical reaction. chemical reaction.
Catalysts are Catalysts are unchangedunchanged in a in a chemical reaction. They are neither chemical reaction. They are neither reactants nor products. reactants nor products.
Catalysts are written Catalysts are written aboveabove the yield the yield sign.sign.
22
MnO2 2 2H O H O + O
Law of Conservation of Law of Conservation of MassMass Mass is neither Mass is neither createdcreated nor nor destroyeddestroyed in a in a
chemical reaction, it can only chemical reaction, it can only changechange formform.. Mass of the reactants is the Mass of the reactants is the SAMESAME as the mass as the mass
of the products.of the products. The number of each type of atom in the The number of each type of atom in the
reactants must be reactants must be equalequal to the number of to the number of atoms in the atoms in the productsproducts..
Since the number of atoms is the same, the Since the number of atoms is the same, the massmass will be the same on both sides of the will be the same on both sides of the reaction.reaction.
Also, the Also, the typestypes of elements will be the same of elements will be the same on each side.on each side.
Balancing EquationsBalancing EquationsHH2 (g)2 (g) + Cl + Cl2 (g)2 (g) → HCl → HCl (g) (g)
Reactant sideReactant side Product sideProduct side
# of H atoms = 2# of H atoms = 2 # of H atoms = 1# of H atoms = 1
# of Cl atoms = 2# of Cl atoms = 2 # of Cl atoms = 1# of Cl atoms = 1
Does this equation have the same number of atoms Does this equation have the same number of atoms of each element on both sides of the equation? of each element on both sides of the equation?
Therefore, it Therefore, it does notdoes not follow the Law of follow the Law of Conservation of Mass. Conservation of Mass.
NO!!!
Balancing Equations Balancing Equations (cont.)(cont.)
HH2 (g)2 (g) + Cl + Cl2 (g)2 (g) → HCl→ HCl(g) (g)
This equation is called a This equation is called a skeletonskeleton equation.equation.
This equation must be This equation must be balancedbalanced with with coefficientscoefficients (the number in front of a (the number in front of a formula for a substance).formula for a substance).
a BALANCED a BALANCED Equation…Equation…
HH2 (g)2 (g) + Cl + Cl2 (g)2 (g) → → 22HClHCl(g)(g)
Reactant sideReactant side Product sideProduct side
# of H atoms = 2# of H atoms = 2 # of H atoms = # of H atoms = 22
# of Cl atoms = 2# of Cl atoms = 2 # of Cl atoms = # of Cl atoms = 22
A coefficient of 1(one) is understood and is not A coefficient of 1(one) is understood and is not necessary in the balanced chemical equation.necessary in the balanced chemical equation.
Steps for balancing Steps for balancing equationsequations
1.1. Write the chemical formula for each Write the chemical formula for each reactant and product.reactant and product.
2.2. Indicate the state of each substance.Indicate the state of each substance.
3.3. Use Use coefficientscoefficients in front of the in front of the substance to balance the equation. substance to balance the equation. The The number of each number of each atomatom should should be the be the SAMESAME on both sides of the on both sides of the equation.equation.
NOTE: NOTE: NEVERNEVER CHANGE SUBSCRIPTS!!! CHANGE SUBSCRIPTS!!!
Balancing ExamplesBalancing Examples1.1. HH22 + Br + Br22 → → 22HBrHBr
2.2. 22Na + ClNa + Cl22 → → 22NaClNaCl
3.3. 44Na + ONa + O22 → → 22NaNa22OO
4.4. Zn + Zn + 22HCl → ZnClHCl → ZnCl22 + H + H22
5.5. 44Fe + Fe + 33OO22 → → 22FeFe22OO33
Balancing ExamplesBalancing Examples6.6. PP44
+ + 55OO22 → → 22PP22OO55
7.7. AlAl22OO33 + + 33HH22 → → 22Al Al + + 33HH22OO
8.8. 22Ca + OCa + O2 2 → → 22CaOCaO
9.9. 33ClCl22 + + 22AlBrAlBr33 → → 33BrBr22 + + 22AlClAlCl33
10.10. 22HgO → HgO → 22Hg + OHg + O22
Synthesis ReactionsSynthesis Reactions
Two or more reactants produce Two or more reactants produce ONEONE productproduct
A.K.A. A.K.A. Direct combinationDirect combination reactants reactants
Follows the pattern: Follows the pattern: A + B A + B → AB→ AB**only **only ONEONE product** product**
NN22 + 3H + 3H22 → 2NH→ 2NH33
22 reactants reactants → → 11 product product
Synthesis ReactionSynthesis Reaction
Combustion Combustion ReactionsReactions
Chemical reaction involving Chemical reaction involving oxygen (Ooxygen (O22)) in which in which lightlight and and heatheat are produced. are produced. Heat is a useful product. Heat is a useful product.
When fuels are burned in the presence of When fuels are burned in the presence of oxygen, oxygen, water (Hwater (H22O)O) and and carbon carbon dioxide (COdioxide (CO22)) are often produced. are often produced.
Follows the pattern: BC + A Follows the pattern: BC + A → BA + CA→ BA + CA
CHCH4 (g)4 (g) + 2O + 2O2 (g)2 (g) → CO → CO2 (g)2 (g) + 2H + 2H22OO(g)(g) + + heatheat
Combustion ReactionCombustion Reaction
Decomposition Decomposition ReactionsReactions
Opposite of Opposite of synthesissynthesis reactions reactions Substance breaks down into Substance breaks down into simpler simpler
substances.substances. Chemists can cause decomposition, but Chemists can cause decomposition, but
decomposition can also be decomposition can also be spontaneousspontaneous..
AB AB → A + B→ A + B
Only Only ONEONE reactant! reactant!
2H2H22O → 2HO → 2H22 + O + O22
11 reactant → reactant → 22 productsproducts
Single Displacement Single Displacement (Replacement) Reactions(Replacement) Reactions
Change in Change in bonds.bonds.One substance will One substance will replacereplace, or , or bump bump
outout, another element in a compound., another element in a compound.
AA + + BBC C → → AAC + C + BB(2 reactants – element and compound(2 reactants – element and compound2 products – element and compound)2 products – element and compound)
ZnZn + + HH22SOSO44 → → ZnZnSOSO44 + + HH22
Double Displacement Double Displacement (Replacement) Reactions(Replacement) Reactions
Both substances change Both substances change partnerspartners
AABB + + CCDD → → AADD + + CCBB
22KKII(aq)(aq) + + PbPb(NO(NO33))22 (aq)(aq) 22KKNONO33(aq)(aq) + + PbPbII22(s) (s)
2 reactants (both compounds) and 2 reactants (both compounds) and 2 products (both compounds)2 products (both compounds)
Synthesis
Decomposition
SR
DR
Energy Changes in Energy Changes in ReactionsReactions
ExothermicExothermic Reactions Reactions ReleaseRelease heat into the surroundings heat into the surroundings
Surroundings will get Surroundings will get hotterhotter..
Sometimes need heat to them started.Sometimes need heat to them started.
A noticeable A noticeable increaseincrease in temperature in temperature occurs. occurs.
Ex. Ex. Combustion & Burning MgCombustion & Burning Mg
Energy Changes in Energy Changes in ReactionsReactions
EndothermicEndothermic Reactions Reactions AbsorbAbsorb heat from the surroundings. heat from the surroundings.
Surroundings will get Surroundings will get coolercooler. .
Need heat to keep them going.Need heat to keep them going.
A noticeable A noticeable decreasedecrease in temperature in temperature occurs.occurs.
Ex. Ex. Photosynthesis and cold packsPhotosynthesis and cold packs
The reactivity of a metal is based on its The reactivity of a metal is based on its ability to ability to replacereplace another in a compound. another in a compound. The metal is oxidized. The metal is oxidized.
If a single replacement reaction occurs, the If a single replacement reaction occurs, the metal that “cuts in” is metal that “cuts in” is MOREMORE reactive than reactive than the one that was removed or replaced.the one that was removed or replaced.
An An activity seriesactivity series of metals is a listing of metals is a listing that ranks metals according to their that ranks metals according to their reactivityreactivity.. The The most most active metal is at the active metal is at the TOPTOP of the list of the list The The least least active metal is at the active metal is at the BOTTOMBOTTOM of the of the
listlist
Reactivity or Activity of Reactivity or Activity of MetalsMetals
The The ACTIVITY SERIESACTIVITY SERIES is listed below is listed below::lithiumlithiumpotassiumpotassiumbariumbariumstrontiumstrontiumcalciumcalciumsodiumsodiummagnesiummagnesiumaluminumaluminummanganesemanganesezinczincironironcadmiumcadmiumcobaltcobaltnickelnickeltintinleadleadhydrogenhydrogencoppercoppersilversilvermercurymercurygoldgold
The most active metal is LITHIUM
The least active metal is GOLD
Which is more active nickel or iron? IRON
Examples of the Examples of the Activity of MetalsActivity of Metals
Al + CuClAl + CuCl22 Cu + AlCl Cu + AlCl33
Mg + HCl Mg + HCl H H22 + MgCl + MgCl22
Cu + HCl Cu + HCl No Reaction! No Reaction!
Treatment of Treatment of MetalsMetals
Metals are treated to protect from Metals are treated to protect from corrosioncorrosion or to make the metals or to make the metals better suited for specific purposes, better suited for specific purposes, such as, improving such as, improving strengthstrength or or making them making them more light weightmore light weight..
Types of Metal TreatmentsTypes of Metal TreatmentsGalvanizing Galvanizing = = coating with zinc coating with zinc
(electroplating)(electroplating)Painting = Painting = painting helps prevent painting helps prevent
corrosioncorrosionMaking Making alloysalloys = = mixture of 2/more mixture of 2/more
metals or a metal and a nonmetalmetals or a metal and a nonmetal. .
Common AlloysCommon AlloysBronzeBronzeBrassBrassSteelSteelStainless steelStainless steelPewterPewterSolderSolder
copper + tin
copper + zinc
iron + carbon
iron, carbon + chromium
lead, tin + silver
copper, tin + antimony