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Types of Reactions. Unit C – Chemical Reactions. Chemical equations. Chemical reaction: a process in which substances interact, causing new substances with different properties to form Reactant: a starting substance in a chemical reaction - PowerPoint PPT Presentation
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Types of ReactionsUnit C – Chemical Reactions
Chemical reaction: a process in which substances interact, causing new substances with different properties to form
Reactant: a starting substance in a chemical reaction
Product: a substance that is formed in a chemical reaction
Chemical equations
Chemical equation: a condensed statement that expresses chemical change using symbols and chemical names or formulas
Word equation: a chemical equation in which the reactants and products in a chemical reaction are represented by their chemical names; their relative quantities or states of matter are not included
Chemical equations
Skeleton equation: a chemical equation in which the reactants and products in a chemical reaction are represented by their chemical formulas; their relative quantities or states of matter are not included
Balanced chemical equation: a statement that uses chemical formulas and coefficients to show the identities and ratios of the reactants and products in a chemical reaction
Chemical equations
Coefficient: in a balanced chemical equation, a positive number that is placed in front of a formula to show the relative number of particles of the substance that are involved in the reaction
Example #1iron + oxygen iron(III) oxideFe(s)+ O2(g) Fe2O3(s)
Chemical equations
There are generally 5 types of chemical reactions:1) Synthesis2) Decomposition3) Combustion4) Single displacement5) Double displacement
Chemical reactions
Synthesis reaction: a chemical reaction in which two or more reactants combine to produce a single compound
There are 3 general types of synthesis reactions:1) 2 elements react to form a binary compound2) 1 element reacts with 1 compound to form a
new compound3) 2 compounds react to form a new compound
Synthesis
2 elements react to form a binary compound◦ A univalent metal reacts with a non-metal to
form an ionic compoundExample #1
2 Na(s) + Cl2(g) 2 NaCl(s)
Synthesis
2 elements react to form a binary compound◦ A multivalent metal reacts with a non-metal to
form various ionic compoundsExample #1
2 Cu(s) + Cl2(g) 2 CuCl(s)Example #2
Cu(s) + Cl2(g) CuCl2(s)
Synthesis
2 elements react to form a binary compound◦ Two non-metals react to form a molecular
compoundExample #1
C(s) + O2(g) CO2(g)Example #2
2 C(s) + O2(g) 2 CO(g)
Synthesis
1 element reacts with 1 compound to form a new compound
Example #12 SO2(g) + O2(g) 2 SO3(g)
Example #2PCl3(ℓ) + Cl2(g) PCl5(s)
Synthesis
2 compounds react to form a new compound◦ A non-metal oxide reacting with water to form
an acidExample #1
CO2(g) + H2O(ℓ) H2CO3(aq)Example #2
SO3(g) + H2O(ℓ) H2SO4(aq)
Synthesis
2 compounds react to form a new compound◦ A metal oxide reacting with water to form a
baseExample #1
Na2O(s) + H2O(ℓ) 2 NaOH(aq)Example #2
MgO(s) + H2O(ℓ) Mg(OH)2(aq)
Synthesis
Decomposition reaction: a chemical reaction in which a compound breaks down into elements or simpler compounds
There are 4 general types of decomposition reactions (and a few special ones):1) A binary compound decomposing into its elements2) A metal nitrate decomposing into a metal nitrite and
oxygen gas3) A metal carbonate decomposing into a metal oxide and
carbon dioxide4) A metal hydroxide decomposing into a metal oxide and
water5) Special reactions
Decomposition
A binary compound decomposing into its elementsExample #1
2 NaCl(s) 2 Na(s) + Cl2(g)Example #2
2 HgO(s) 2 Hg(ℓ) + O2(g)
A metal hydroxide decomposing into a metal oxide and water
Example #1Ca(OH)2(s) CaO(s) + H2O(g)
Decomposition
A metal nitrate decomposing into a metal nitrite and oxygen gas
Example #12 NaNO3(s) 2 NaNO2(s) + O2(g)
A metal carbonate decomposing into a metal oxide and carbon dioxide
Example #1CaCO3(s) CaO(s) + CO2(g)
Sr(OH)2 (s) H2O(l) + SrO(s)
Decomposition
Special reactions◦ TNT (tri-nitro-toluene), dynamite
Example #12 C7H5N3O6(s) 3 N2(g) + 5 H2O(g) + 7 CO(g) + 7 C(s)
◦ Air bags (sodium azide):Example #1
2 NaN3(s) 2 Na(s) + 3 N2(g)
Decomposition
Special reactions◦ Rocket thrusters (hydrazine):
Example #13 N2H4(ℓ) 4 NH3(g) + N2(g)N2H4(ℓ) N2(g) + 2 H2(g)
Decomposition
Combustion reaction: the reaction of a substance with oxygen, producing one or more oxides, heat, and light
Hydrocarbon: a compound that is composed only of the elements carbon and hydrogen
There are 2 general types of combustion of hydrocarbon reactions:1) Complete combustion2) Incomplete combustion
Combustion
Prefixes used in naming hydrocarbonsNumber of
carbon atoms
Prefix Alkane (CnH2n+2) Formula
1 Meth~ Methane CH4
2 Eth~ Ethane C2H6
3 Prop~ Propane C3H8
4 But~ Butane C4H10
5 Pent~ Pentane C5H12
6 Hex~ Hexane C6H14
7 Hept~ Heptane C7H16
8 Oct~ Octane C8H18
9 Non~ Nonane C9H20
10 Dec~ Decane C10H22
Combustion
Complete combustion occurs when the only products are carbon dioxide (CO2) and water (H2O)
Example #1C3H8(g) + O2(g) CO2(g) + H2O(ℓ)
Combustion
Incomplete combustion occurs when the products are carbon dioxide (CO2) and water (H2O) AS WELL AS carbon monoxide (CO) and carbon/soot (C)
Soot: fine particles consisting mostly of carbon, formed during the incomplete combustion of a hydrocarbon
Example #12 C3H8(g) + 7 O2(g) 2 CO2(g) + 8 H2O(ℓ) + 2 CO(g) + 2 C(s)2 C3H8(g) + 7 O2(g) CO2(g) + 8 H2O(ℓ) + 4 CO(g) + C(s)2 C3H8(g) + 6 O2(g) CO2(g) + 8 H2O(ℓ) + 2 CO(g) + 3 C(s)
Combustion
Combustion reactions can also occur between oxygen and many other substances
Some of these reactions are not only combustion reactions, but synthesis reactions as well
Example #12 H2(g) + O2(g) 2 H2O(g)
Example #22 Mg(s) + O2(g) 2 MgO(s)
Combustion
Combustion also occurs inside living organisms An example of this is the combustion of glucose
which is a chemical reaction necessary for life (cellular respiration)
Example #1C6H12O6(s) + O2(g) 6 CO2(g) + 6 H2O(g)
Although both combustion and cellular respiration are similar chemical reactions, there are some notable differences among the two processes
Combustion
Characteristics Combustion Cellular Respiration
Speed Is a faster process Is a slower process
Temperature Generally occurs at high temperatures
Occurs at body temperatures
Complete/incomplete
reaction
May be incomplete, producing soot and carbon monoxide
Always complete, producing carbon dioxide, water, and
energyDuration Is not a continuous
processOccurs at all times within living cells
Combustion
Single displacement reaction: a chemical reaction in which one element in a compound is replaced (displaced) by another element
Activity series (metal & non-metal): a ranking of the relative reactivity of metals or halogens in aqueous reactions
There are 3 general types of single displacement reactions:1) A metal displacing another metal from an ionic compound
(involves activity series of metals)2) A metal displacing hydrogen from acid or water (involves
activity series of metals)3) A non-metal displacing another non-metal from an ionic
compound (involves activity series of non-metals)
Single displacement
A metal displacing another metal from an ionic compound (involves activity series of metals)
Example #1Cu(s) + 2 AgNO3(aq) Cu(NO3)2(aq) + 2 Ag(s)
Example #2Cu(s) + Al(NO3)3(aq) No reaction
Single displacement
A metal displacing hydrogen from acid or water (involves activity series of metals)
Example #1Mg(s) + 2 HCl(aq) MgCl2(aq) + H2(g)
Example #2Na(s) + H2O(ℓ) NaOH(aq) + H2(g)
Example #3Cu(s) + HCl(aq) No reaction
Single displacement
A non-metal displacing another non-metal from an ionic compound (involves activity series of non-metals)
Example #1Cl2(g) + 2 NaBr(aq) 2 NaCl(aq) + H2(g)
Single displacement
[organizational chart summarizing all 5 types and subcategories]
Chemical reactions
[include 2010 and 2003 MHR Chemistry 11 textbooks]
References