chemicals reaction

Types of Chemical Types of Chemical ReactionsReactions

Writing Chemical ReactionsWriting Chemical Reactions

Types of ReactionsTypes of Reactions

Many chemical Many chemical reactions have reactions have defining defining characteristics characteristics which allow which allow them to be them to be classified as to classified as to type.type.


The five types of chemical reactions The five types of chemical reactions in this unit are:in this unit are: CombinationCombination DecompositionDecomposition Single ReplacementSingle Replacement Double ReplacementDouble Replacement CombustionCombustion

Combination ReactionsCombination Reactions

Two or more substances combine to Two or more substances combine to form form one substanceone substance.. The general form is A + X The general form is A + X AXAX

Example:Example: Magnesium + oxygen Magnesium + oxygen

magnesium oxidemagnesium oxide 2Mg + O2Mg + O22 2MgO 2MgO

Magnesium + OxygenMagnesium + Oxygen


Combination reactions may also be Combination reactions may also be called called compositioncomposition or or synthesis synthesis reactionsreactions..

Some types of combination reactions:Some types of combination reactions: Combination of elementsCombination of elements

K + ClK + Cl22 One product will be formedOne product will be formed


K + ClK + Cl22

Write the ions: KWrite the ions: K++ Cl Cl--

Balance the charges: KClBalance the charges: KCl

Balance the equation: Balance the equation: 22K + ClK + Cl2 2 22KClKCl


Some types of combination Some types of combination reactions:reactions: Oxide + water Oxide + water

Nonmetal oxide + water Nonmetal oxide + water acid acidSOSO22 + H + H22O O H H22SOSO33

Metal oxide + water Metal oxide + water base baseBaO + HBaO + H22O O Ba(OH) Ba(OH)22


Some types of combination Some types of combination reactions:reactions: Metal oxides + nonmetal Metal oxides + nonmetal

oxidesoxidesNaNa22O + COO + CO22 Na Na22COCO33

CaO + SOCaO + SO2 2 CaSO CaSO33

Decomposition Decomposition ReactionsReactions

One substance reacts to form two or One substance reacts to form two or more substances. more substances. The general form is AX The general form is AX A + X A + X

Example:Example: Water can be decomposed by Water can be decomposed by

electrolysis.electrolysis. 2H2H22O O 2H 2H22 + O + O22

Electrolysis of WaterElectrolysis of Water


Types of Decomposition Reactions:Types of Decomposition Reactions: Decomposition of carbonatesDecomposition of carbonates

When heated, some When heated, some carbonatescarbonates break down to form an break down to form an oxideoxide and and carbon dioxidecarbon dioxide..

CaCOCaCO33 CaO + CO CaO + CO22

HH22COCO33 H H22O + COO + CO22


Types of decomposition reactions:Types of decomposition reactions: Some Some metal hydroxidesmetal hydroxides decompose decompose

into into oxidesoxides and and waterwater when heated. when heated.Ca(OH)Ca(OH)22 CaO + H CaO + H22OO

Note that this is the reverse of a Note that this is the reverse of a similar combination reaction.similar combination reaction.


Types of decomposition reactions:Types of decomposition reactions: Metal chloratesMetal chlorates decompose into decompose into

chlorideschlorides and and oxygenoxygen when heated. when heated.2KClO2KClO33 2KCl + 3O 2KCl + 3O22

Zn(ClOZn(ClO33))22 ZnCl ZnCl22 + 3O + 3O22

Some of these reactions are used in Some of these reactions are used in explosives.explosives.


Some substances can easily Some substances can easily decompose:decompose: Ammonium hydroxide is actually Ammonium hydroxide is actually

ammonia gas dissolved in water.ammonia gas dissolved in water.NHNH44OH OH NH NH33 + H + H22OO

Some acids decompose into water Some acids decompose into water and an oxide.and an oxide.HH22SOSO33 H H22O + SOO + SO22


Some decomposition reactions Some decomposition reactions are difficult to predict.are difficult to predict.

The decomposition of nitrogen The decomposition of nitrogen triiodide, NItriiodide, NI33, is an example of an , is an example of an interesting decomposition interesting decomposition reaction.reaction.

Nitrogen triiodideNitrogen triiodide

Single Replacement Single Replacement ReactionsReactions

A metal will replace a metal ion in a A metal will replace a metal ion in a compound.compound. The general form is A + BX The general form is A + BX AX + B AX + B

A nonmetal will replace a nonmetal A nonmetal will replace a nonmetal ion in a compound.ion in a compound. The general form is Y + BX The general form is Y + BX BY + X BY + X


Examples:Examples: Ni + AgNONi + AgNO33

Nickel replaces the metallic ion AgNickel replaces the metallic ion Ag++.. The silver becomes free silver and the The silver becomes free silver and the

nickel becomes the nickel(II) ion.nickel becomes the nickel(II) ion. Ni + AgNONi + AgNO33 Ag + Ni(NO Ag + Ni(NO33))22

Balance the equation:Balance the equation: Ni + 2AgNONi + 2AgNO33 2Ag + Ni(NO 2Ag + Ni(NO33))

Metal TreeMetal Tree


Not all single replacement reactions Not all single replacement reactions that can be written actually happen. that can be written actually happen.

The metal must be more active than The metal must be more active than the metal ion.the metal ion.

Aluminum is more active than iron in Aluminum is more active than iron in Al + FeAl + Fe22OO33 in the following reaction: in the following reaction:

Thermite ReactionThermite Reaction

Thermite ReactionThermite Reaction

Al + FeAl + Fe22OO33 Aluminum will replace iron(III) as Aluminum will replace iron(III) as

was seen in the video.was seen in the video. Iron(III) becomes Fe and Iron(III) becomes Fe and

aluminum metal becomes Alaluminum metal becomes Al3+3+.. 22Al + FeAl + Fe22OO33 22Fe + AlFe + Al22OO33


An active nonmetal can replace a An active nonmetal can replace a less active nonmetal.less active nonmetal. The halogen (FThe halogen (F22, Cl, Cl22, Br, Br22, I, I22) )

reactions are good examples.reactions are good examples. FF22 is the most active and I is the most active and I22 is is

the least.the least.ClCl22 +2 NaI +2 NaI 2 NaCl + I 2 NaCl + I22

Double Replacement Double Replacement ReactionsReactions

Ions of two compounds exchange Ions of two compounds exchange places with each other.places with each other. The general form is AX + BY The general form is AX + BY

AY + BXAY + BX

MetathesisMetathesis is an alternate name is an alternate name for double replacement reactions.for double replacement reactions.

NaOH + CuSONaOH + CuSO44

Double ReplacementDouble Replacement

NaOH + CuSONaOH + CuSO44 The NaThe Na++ and Cu and Cu2+2+ switch places. switch places. NaNa++ combines with SO combines with SO44

2-2- to form Na to form Na22SOSO4.4.

CuCu2+2+ combines with OH combines with OH-- to form Cu(OH) to form Cu(OH)22

NaOH + CuSONaOH + CuSO44 Na Na22SOSO44 + Cu(OH) + Cu(OH)22

22NaOH + CuSONaOH + CuSO44 Na Na22SOSO44 + Cu(OH) + Cu(OH)22

CuSOCuSO44 + Na + Na22COCO33


CuSOCuSO44 + Na + Na22COCO33 CuCu2+ 2+ combines with COcombines with CO33

2-2- to form to form CuCOCuCO33..

NaNa++ combines with SO combines with SO442-2- to form to form

NaNa22SOSO44.. CuSOCuSO44 + Na + Na22COCO33 CuCO CuCO33 + Na + Na22SOSO44

NaNa22COCO33 + HCl + HCl


NaNa22COCO33 + HCl + HCl Notice that gas bubbles were Notice that gas bubbles were

produced rather than a produced rather than a precipitate.precipitate.

What was the gas?What was the gas? Write the double replacement Write the double replacement

reaction first.reaction first.


NaNa22COCO33 + HCl + HCl NaNa++ combines with Cl combines with Cl-- to form NaCl. to form NaCl. HH++ combines with CO combines with CO33

2-2- to form H to form H22COCO33.. NaNa22COCO33 + 2HCl + 2HCl 2NaCl + H 2NaCl + H22COCO33

HH22COCO33 breaks up into H breaks up into H22O and COO and CO22..


The gas formed was carbon dioxide.The gas formed was carbon dioxide. The final balanced reaction is: The final balanced reaction is:

NaNa22COCO3 3 + HCl + HCl NaCl + H NaCl + H22O + COO + CO22.. Balance the equation.Balance the equation. NaNa22COCO33 + 2HCl + 2HCl 2NaCl + H 2NaCl + H22O + COO + CO22

Combustion ReactionCombustion Reaction When a substance combines with When a substance combines with

oxygen, a combustion reaction oxygen, a combustion reaction results.results.

The combustion reaction may also The combustion reaction may also be an example of an earlier type be an example of an earlier type such as 2Mg + Osuch as 2Mg + O22 2MgO. 2MgO.

The combustion reaction may be The combustion reaction may be burning of a fuel.burning of a fuel.

Combustion ReactionCombustion Reaction

Methane, CHMethane, CH44, is natural gas., is natural gas. When hydrocarbon compounds are When hydrocarbon compounds are

burned in oxygen, the products burned in oxygen, the products are water and carbon dioxide.are water and carbon dioxide.

CHCH44 + O + O22 CO CO22 + H + H22OO CHCH44 + 2O + 2O22 CO CO22 + 2H + 2H22OO

Combustion ReactionsCombustion Reactions

Combustion reactions involve light Combustion reactions involve light and heat energy released.and heat energy released.

Natural gas, propane, gasoline, etc. Natural gas, propane, gasoline, etc. are burned to produce heat energy.are burned to produce heat energy.

Most of these organic reactions Most of these organic reactions produce water and carbon dioxide.produce water and carbon dioxide.

PracticePractice Classify each of the following as to Classify each of the following as to

type:type:

HH22 + Cl + Cl22 2HCl 2HCl CombinationCombination

Ca + 2HCa + 2H22O O Ca(OH) Ca(OH)22 + H + H22

Single replacementSingle replacement

PracticePractice

2CO + O2CO + O22 2CO 2CO22

Combination and combustionCombination and combustion

2KClO2KClO33 2KCl + 3O 2KCl + 3O22

DecompositionDecomposition

PracticePractice

FeS + 2HCl FeS + 2HCl FeCl FeCl22 + H + H22SS Double replacementDouble replacement

Zn + HCl Zn + HCl ? ? Single replacementSingle replacement Zn + 2HCl Zn + 2HCl ZnCl ZnCl22 + H + H22


Read Chapter 8-2Read Chapter 8-2

Review nomenclatureReview nomenclature

Do all of the practice exercises Do all of the practice exercises given in class.given in class.

chemicals reaction

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