Chemical Reactions

Types of ChemicalReactions

Honors Chemistry Ch 8

Types of ReactionsTypes of Reactions

Classification of chemical reactions enablesus to organize information and ultimatelypredict the results of similar reactionswithout having to carry them outexperimentally.

Being able to identify the type of reactionhelps you predict the product(s)

Steps to Writing ReactionsSteps to Writing Reactions

••Some steps for doing reactions

1.1.Identify the type of reaction

2.2.Predict the product(s) using the type ofreaction as a model

3.3.Write the skeleton reaction and then balance it

Don’t forget about the diatomic elements!(HOFBrINCl) For example, Oxygen is O2 as anelement.

In a compound, it can’t be a diatomic elementbecause it’s not an element anymore, it’s acompound!

1. Synthesis reactions1. Synthesis reactions

••Synthesis reactions occur when two substances (generallyelements) combine and form a compound. (Sometimesthese are called combination or addition reactions.)

Examples: calcium + sulfur  calcium sulfide

carbon dioxide + sodium oxide  sodium carbonate

In other words: element + element compound or

Simple compound + simple compound complex compound

PracticePractice

••Predict the products. Write and balancethe following synthesis reaction equations.

Ex. 1: Sodium metal reacts with chlorine gas 

Ex 2: phosphorus + oxygen  diphosphorus pentoxide

Synthesis ReactionsSynthesis Reactions

••Here is another example of a synthesisreaction

2. Decomposition Reactions2. Decomposition Reactions

Decomposition reactions occur when a compoundbreaks up into the elements or in a few to simplercompounds

Examples: iron(III) sulfide  iron + sulfur

Sodium hydrogen carbonate  sodium hydroxide+ carbon dioxide

In other words:

compound element + element or

Complex compound  compound + compound

Let’s PracticeLet’s Practice

••Predict the products. Then, write andbalance the following decompositionreaction equations:

••Ex. 3: copper(I) chloride 

••Ex 4: water

Decomposition ReactionsDecomposition Reactions

••Another view of a decomposition reaction:

3. Single Replacement Reactions3. Single Replacement Reactions

Single Replacement Reactions occur when one elementreplaces another in a compound.

••A metal can replace a metal (+) OR a nonmetal can replace a nonmetal (-)

••Examples:

••calcium oxide + magnesium  magnesium oxide + calcium

••calcium chloride + fluorine  calcium fluoride + chlorine

••In other words: element + compoundelement + compound

A + BC  AC + B (if A is a metal) OR

A + BC  BA + C (if A is a nonmetal)

(remember the cation always goes first!)

Single Replacement ReactionsSingle Replacement Reactions

••Another view:

Let’s PracticeLet’s Practice

Write and balance the following singlereplacement reaction equation:Write and balance the following singlereplacement reaction equation:

Ex 5: aluminum + barium chlorideEx 5: aluminum + barium chloride

Ex. 6: ammonium oxide + iodineEx. 6: ammonium oxide + iodine

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The Activity SeriesThe Activity Series

In order for an element to replace another, it must be moreactive. If this is not the case, then no reaction occurs.In order for an element to replace another, it must be moreactive. If this is not the case, then no reaction occurs.

A. chromium + lead (II) chloride A. chromium + lead (II) chloride 

B. zinc + potassium hydroxide B. zinc + potassium hydroxide 

C. magnesium + sulfuric acidC. magnesium + sulfuric acid

D. iodine + sodium chlorideD. iodine + sodium chloride

C. fluorine + sodium chlorideC. fluorine + sodium chloride

4. Double Replacement Reactions4. Double Replacement Reactions

Double Replacement Reactions occur when a metal replacesa metal in a compound and a nonmetal replaces a nonmetal in acompound

••Example: silver nitrate + sodium chloride  sodium nitrate +silver chloride

••In other words:

••Ionic Cmpd + ionic cmpd  different cmpd+ different cmpd

••AB + CD  AD + CB

Double Replacement ReactionsDouble Replacement Reactions

••Think about it like “foil”ing in algebra, first andlast ions go together + inside ions go together

••Example:

AgNO3(aq) + NaCl(s)  AgCl(s) + NaNO3(aq)

••Another example:

K2SO4(aq) + Ba(NO3)2(aq)  KNO3(aq) + BaSO4(s)

Let’s PracticeLet’s Practice

••Predict the products. Balance the equation

Example 8: sodium chloride + aluminum oxide 

Example 9:Example 9:

potassium permanganate + calcium phosphatepotassium permanganate + calcium phosphate

There are three types of products that drivedouble replacement reactionsThere are three types of products that drivedouble replacement reactions

1. Formation of an insoluble or slightlysoluble precipitate1. Formation of an insoluble or slightlysoluble precipitate

2. Formation of a gaseous product2. Formation of a gaseous product

3. formation of a molecular compound-likewater3. formation of a molecular compound-likewater

5. Combustion Reactions5. Combustion Reactions

••Combustion reactionsoccur when a hydrocarbonreacts with oxygen gas.

••This is also calledburning!!! In order to burnsomething you need the 3things in the “firetriangle”:1) A Fuel (hydrocarbon)2) Oxygen to burn it with3) Something to ignite thereaction (spark)

Combustion ReactionsCombustion Reactions

••In general:CxHy + O2  CO2 + H2O

••Products in combustion areALWAYS carbon dioxide andwater. (although incompleteburning does cause some by-products like carbon monoxide)

••Combustion is used to heathomes and run automobiles(octane, as in gasoline, is C8H18)

CombustionCombustion

Examples:

methane + oxygen  carbon dioxide + water

C8H18 + O2  CO2 + H2O

In other words: hydrocarbon + oxygen carbon dioxide + water vapor

Let’s practiceLet’s practice

Write the products and balance thefollowing combustion reaction:Write the products and balance thefollowing combustion reaction:

Example 10: C6H6 + O2 Example 10: C6H6 + O2 

Example 11: C2H5OH + O2 Example 11: C2H5OH + O2 

Neutralization reactionNeutralization reaction

In other words: acid + base  salt + waterIn other words: acid + base  salt + water

Ex 12: hydrochloric acid + sodium hydroxide Ex 12: hydrochloric acid + sodium hydroxide 

HCl + NaOH  NaCl + HOHHCl + NaOH  NaCl + HOH

Ex 13: potassium hydroxide + sulfuric acid Ex 13: potassium hydroxide + sulfuric acid 

KOH +HCl  KCl +HOHKOH +HCl  KCl +HOH

Net ionic precipitation reaction*** more to come on this***Net ionic precipitation reaction*** more to come on this***

In other words:In other words:

aqueous ion + aqueous ion  solid precipitateaqueous ion + aqueous ion  solid precipitate

Ex 14: aqueous silver ion + aqueous chloride Ex 14: aqueous silver ion + aqueous chloride 

Ag+1(aq) + Cl-1(aq)  AgCl(s)

Ex: 15: aqueous lead(II) ion + aqueous hydroxide Ex: 15: aqueous lead(II) ion + aqueous hydroxide 

Pb+2(aq) + 2OH-1(aq)  Pb(OH)2 (s)

Dissociation reactionDissociation reaction

In other words: solid soluble salt or base component ionsIn other words: solid soluble salt or base component ions

Ex 16: iron(III) chloride dissolves in water Ex 16: iron(III) chloride dissolves in water 

FeCl3 (s)  Fe+3(aq) + 3 Cl-1(aq)

Ex 17: barium hydroxide dissolved in water Ex 17: barium hydroxide dissolved in water 

Ba(OH)2 (s)  Ba+2(aq) + 2 OH-1(aq)

Ionization reactionIonization reaction

In other words:In other words:

acid + water  hydronium ion + anionacid + water  hydronium ion + anion

Ex 18: hydrochloric acid reacts with water Ex 18: hydrochloric acid reacts with water 

HCl + H2O  H3O+1(aq) + Cl-1(aq)

Ex 19: sulfuric acid reacts with water Ex 19: sulfuric acid reacts with water 

H2SO4 + H2O  H3O+1(aq) + HSO4-1(aq)