Types of Chemical Reactions

Thermite reaction

Types of ReactionsTypes of Reactions

• There are five types of chemical reactions we will talk about:

1. Synthesis reactions

2. decomposition reactions

3. Single replacement reactions

4. Double replacement reactions

5. Combustion reactions

• You need to be able to identify the type of reaction and predict the product(s)

Steps to Writing ReactionsSteps to Writing Reactions• Some steps for doing reactions

1. Identify the type of reaction

2. Predict the product(s) using the type of reaction as a model

3. Balance it

Reminder!Reminder!

1. Don’t forget about the diatomic elements! For example, Oxygen is O2 as an element.

2. In a compound, (MgO) it can’t be a diatomic element because it’s not an element anymore, it’s a compound!

1. Synthesis reactions1. Synthesis reactions

• Synthesis reactions occur when two substances (generally elements) combine and form a compound. (Sometimes these are called combination or addition reactions.)

SYNTHESIS SYNTHESIS GENERAL FORMULAGENERAL FORMULA

reactant + reactant 1 product• Basically: A + B AB

• Example: 2H2 + O2 2H2O

• Example: C + O2 CO2

Synthesis ReactionsSynthesis Reactions

• Here is another example of a synthesis reaction

PracticePractice

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

• Sodium metal reacts with chlorine gas

Na(s) + Cl2(g) • Solid Magnesium reacts with fluorine gas

Mg(s) + F2(g) • Aluminum metal reacts with fluorine gas

Al(s) + F2(g)

2. Decomposition Reactions2. Decomposition Reactions• Decomposition

reactions occur when a compound breaks up into the elements or into a few simpler compounds

DecompositionDecompositionGENERAL FORMULAGENERAL FORMULA

• 1 Reactant Product + Product • In general: AB A + B• Example: 2 H2O 2H2 + O2

• Example: 2 HgO 2Hg + O2

Decomposition ReactionsDecomposition Reactions

• Another view of a decomposition reaction:

Decomposition ExceptionsDecomposition Exceptions

• Carbonates are a special case of a decomposition reaction that does not go to the elements.• Carbonates (CO3

2-) decompose to carbon dioxide and a metal oxide

• Example: CaCO3 CO2 + CaO

• There are other special cases, but we will not explore those in High School Chemistry

PracticePractice

• Predict the products. Then, write and balance the following decomposition reaction equations:

• Solid Lead (IV) oxide decomposes• PbO2(s)

• Aluminum nitride decomposes • AlN(s)

PracticePractice

Identify the type of reaction for each of the following synthesis or decomposition reactions, and write the balanced equation:

N2(g) + O2(g)

BaCO3(s)

Co(s)+ S(s)

NH3(g) + H2CO3(aq)

NI3(s)

(Co+3)

(Nitrogen monoxide)

Warm-UpWarm-Up

Sodium metal reacts with water to produce Sodium metal reacts with water to produce aqueous sodium hydroxide and hydrogen aqueous sodium hydroxide and hydrogen gas. Write the balanced equation for this gas. Write the balanced equation for this reaction.reaction.2Na2Na(g)(g) + 2H + 2H22OO(l)(l) 2NaOH 2NaOH(aq)(aq) + H + H22(g)(g)

Balance the equationBalance the equationCC66HH1414 + O + O22 CO CO22 + H + H22OO

2C2C66HH1414 + 19O + 19O22 12CO 12CO22 + 14H + 14H22OO

3. Single Replacement Reactions3. Single Replacement Reactions

• Single Replacement Reactions occur when one element replaces another in a compound.

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

Single ReplacementSingle ReplacementGeneral FormulaGeneral Formula

• element + compound product + product

A + BC AC + B (if A is a metal) CATIONIC OR

A + BC BA + C (if A is a nonmetal) ANIONIC

(remember the cation always goes first!)

When H2O splits into ions, it splits into

H+ and OH- (not H+ and O-2 !!)

Single Replacement ReactionsSingle Replacement Reactions

• Another view:

Trade-off labTrade-off lab

__Al(__Al(ss) + __CuCl) + __CuCl22((aqaq) ) →→ __AlCl __AlCl33((aqaq) + __Cu() + __Cu(ss) )

What type of reaction was the trade-off lab?What type of reaction was the trade-off lab?Single Replacement Reaction Single Replacement Reaction Is it cationic or anionic replacement?Is it cationic or anionic replacement?General form:General form:A + BC A + BC → AC + B→ AC + B

Single Replacement ReactionsSingle Replacement Reactions

• Write and balance the following single replacement reaction equation:

• Zinc metal reacts with aqueous hydrochloric acid

Zn(s) + HCl(aq) ZnCl2 + H2(g)

Note: Zinc replaces the hydrogen ion in the reaction

Is it cationic or anionic?Cationic

2

Single Replacement ReactionsSingle Replacement Reactions• Sodium chloride solid reacts with fluorine gas

NaCl(s) + F2(g) NaF(s) + Cl2(g)

Note that fluorine replaces chlorine in the compound

• Cationic or Anionic?• Anionic

2 2

4. Double Replacement Reactions4. Double Replacement Reactions

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

Double ReplacementDouble ReplacementGeneral FormulaGeneral Formula

• compound + compound product + product• AB + CD AD + CB

Double Replacement ReactionsDouble Replacement Reactions

• Think about it like “foil”ing in algebra, outside 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) 2

Group QuizGroup Quiz

DemoDemoOn a clean piece of paper, write both On a clean piece of paper, write both

group members namesgroup members namesSpeculate as to why specks of solid are Speculate as to why specks of solid are

forming. One paragraph.forming. One paragraph.Turn it into your folderTurn it into your folder

PracticePractice

• Predict the products. Balance the equation1. HCl(aq) + AgNO3(aq)

2. CaCl2(aq) + Na3PO4(aq)

3. Pb(NO3)2(aq) + BaCl2(aq)

4. FeCl3(aq) + NaOH(aq)

5. H2SO4(aq) + NaOH(aq)

6. KOH(aq) + CuSO4(aq)

Warm UpWarm Up

Predict the Products and write the net Predict the Products and write the net ionic equation for the following reactionsionic equation for the following reactions

1. KI (aq) + Pb(NO3)2(aq) →

2. A solution of calcium hydroxide is added to a solution of potassium sulfate

Total Ionic EquationsTotal Ionic Equations Once you write the molecular equation (Double Once you write the molecular equation (Double

replacement), you should check for reactants and replacement), you should check for reactants and products that are soluble or insoluble.products that are soluble or insoluble.

We assume double replacement reactions are in waterWe assume double replacement reactions are in water We can use a solubility table to tell us what We can use a solubility table to tell us what

compounds dissolve in water.compounds dissolve in water. If the compound is If the compound is soluble (dissolves in water), then it (dissolves in water), then it

splits the compound into its component ionssplits the compound into its component ions If the compound is insoluble (does NOT dissolve in If the compound is insoluble (does NOT dissolve in

water), then it remains as a compound and the phase water), then it remains as a compound and the phase label is label is (s).(s).

Solubility TableSolubility Table

Solubility TrendsSolubility Trends

Gases only slightly dissolve in waterGases only slightly dissolve in waterTreat as insolubleTreat as insoluble

Water slightly dissolves in water (HWater slightly dissolves in water (H++ and and OHOH--))Treat as insolubleTreat as insoluble

Strong acids and bases dissolve in waterStrong acids and bases dissolve in waterHydrochloric, Hydrobromic, Hydroiodic, Nitric, Hydrochloric, Hydrobromic, Hydroiodic, Nitric,

Sulfuric, Perchloric AcidsSulfuric, Perchloric AcidsGroup I hydroxidesGroup I hydroxides

Total Ionic EquationsTotal Ionic Equations

Molecular Equation:Molecular Equation:

KK22CrOCrO44 + Pb(NO + Pb(NO33))22 PbCrOPbCrO44 + 2 + 2

KNOKNO33

SolubleSoluble SolubleSoluble Insoluble Insoluble Soluble Soluble

Total Ionic Equation:Total Ionic Equation:

2 K2 K++ + CrO + CrO44 -2-2 + Pb + Pb+2+2 + 2 NO + 2 NO33--

PbCrOPbCrO44 (s) + 2 K (s) + 2 K++ + 2 NO + 2 NO33--

Net Ionic EquationsNet Ionic Equations

These are the same as total ionic These are the same as total ionic equations, but you should cancel out ions equations, but you should cancel out ions that appear on BOTH sides of the equationthat appear on BOTH sides of the equation

Total Ionic Equation:Total Ionic Equation:

2 K2 K++ + CrO + CrO44 -2-2 + Pb + Pb+2+2 + 2 NO + 2 NO33--

PbCrOPbCrO44 (s) + 2 K (s) + 2 K++ + 2 NO + 2 NO33--

Net Ionic Equation:Net Ionic Equation:

CrOCrO44 -2-2 + Pb + Pb+2+2 PbCrO PbCrO44 (s) (s)

Net Ionic EquationsNet Ionic Equations

Try this one! Write the molecular, total ionic, and net Try this one! Write the molecular, total ionic, and net ionic equations for this reaction: Silver nitrate reacts ionic equations for this reaction: Silver nitrate reacts with Lead (II) Chloride in hot water.with Lead (II) Chloride in hot water.

Molecular: Molecular:

Total Ionic:Total Ionic:

Net Ionic:Net Ionic:

5. Combustion Reactions5. Combustion Reactions

• Combustion reactions occur when an element reacts with oxygen gas.

• This is also called burning!!! In order to burn something you need the 3 things in the “fire triangle”:1) A Fuel 2) Oxygen to burn it with3) Something to ignite the reaction (spark)

Combustion ReactionsCombustion Reactions• In general:

Hydrocarbon + O2 CO2 + H2O

Or

Element + O2 element oxide

• Products in combustion are ALWAYS carbon dioxide and water or an oxide

44thth Period brainteaser Period brainteaserClassify, Predict Products (if necessary), & Classify, Predict Products (if necessary), & balancebalance

1. BaCl2(aq) + H2SO4(aq)

2. C6H12 + O2(g)

3. Zn(s) + CuSO4(aq)

4. K(s) + Br2(g) KBr(s)

5. H2O2(aq) O2(g) + H2O(l)

6. Na(s) + O2(g)

Combustion Combustion ReactionsReactions

Edgar Allen Poe’s drooping eyes and mouth are potential signs of CO poisoning.

CO is a by-product of the combustion process if the hydrocarbon does not fully combust.

CombustionCombustion

• Example• C5H12 + 8O2 5CO2 + 6H2O

• Write the products and balance the following combustion reaction:• C4H10 + O2

Activity Series of MetalsActivity Series of Metals Matter tends to react in such Matter tends to react in such

a way that more reactive a way that more reactive substances form less reactive substances form less reactive substances. Some metals substances. Some metals are higher in reactivity than are higher in reactivity than othersothers

Activity series: a list of metals Activity series: a list of metals arranged in decreasing arranged in decreasing reactivity (used for metal and reactivity (used for metal and hydrogen single replacement hydrogen single replacement reactions)reactions)

4242

55thth period Warm-up period Warm-upClassify, Predict Products (if necessary), & Classify, Predict Products (if necessary), & balancebalance

1. BaCl2(aq) + H2SO4(aq)

2. C6H12 + O2(g)

3. Zn(s) + CuSO4(aq)

4. K(s) + Br2(g) KBr(s)

5. H2O2(aq) O2(g) + H2O(l)

6. Na(s) + O2(g)

I will go over the warm-up later in the period.I will go over the warm-up later in the period.

On a blank piece of paper…On a blank piece of paper…

Write one thing you know about chemical Write one thing you know about chemical equations.equations.

Write one thing you need to know but Write one thing you need to know but struggle with about chemical equationsstruggle with about chemical equations

Activity SeriesActivity Series

The higher the metal on the activity series, The higher the metal on the activity series, the more active that metal.the more active that metal.

Translation: higher metals on the chart will Translation: higher metals on the chart will form ions in solution (dissolve in water…ie. form ions in solution (dissolve in water…ie. Aqueous) the other metal in the reaction Aqueous) the other metal in the reaction will precipitate (solid)will precipitate (solid)

Use the activity series on the back of Use the activity series on the back of periodic table to predict products and periodic table to predict products and assign phase labelsassign phase labels

Predict whether a reaction occursPredict whether a reaction occursIf a reaction occurs, predict the If a reaction occurs, predict the products. products. (don’t forget phase labels)(don’t forget phase labels)

Na Na (s)(s) + H + H22O O (l)(l)→→

Fe Fe (s)(s) + HCl + HCl (aq)(aq) →→

Fe Fe (s)(s) + Cr(NO + Cr(NO33))3(aq) 3(aq) →→

Ni Ni (s)(s) + Pb(NO + Pb(NO33))2(aq) 2(aq) →→

Ag Ag (s)(s) + Mg(NO + Mg(NO33))2(aq) 2(aq) →→

Zn Zn (s)(s) + Co(NO + Co(NO33))2(aq) 2(aq) →→

Summary of ReactionsSummary of Reactions

For the test For the test You should be able to ….You should be able to ….

Classify reactionsClassify reactionsPredict ProductsPredict ProductsWrite balanced molecular equationsWrite balanced molecular equationsWrite balanced net ionic equationsWrite balanced net ionic equations

Synthesis and DecompositionSynthesis and Decomposition

General forms:General forms:Synthesis A + B Synthesis A + B → AB→ ABDecomposition AB Decomposition AB → A + B→ A + B If you can’t see the general form of a If you can’t see the general form of a

reaction try labeling the reactants and reaction try labeling the reactants and products with “A” and “B”.products with “A” and “B”.

Know how to classify these reactionsKnow how to classify these reactions

CombustionCombustion

Memorize the two general formsMemorize the two general forms

Hydrocarbon + O2(g) CO2(g) + H2O(l)

Element + O2(g) element oxide

Balancing the first general form can be tricky….. Balancing the first general form can be tricky….. Just keep working at it.Just keep working at it.

You must be able to classify and predict You must be able to classify and predict products in these reactions.products in these reactions.

Single ReplacementSingle Replacement

Use the Activity series on the back of your Use the Activity series on the back of your periodic table to determine whether a reaction periodic table to determine whether a reaction occurs.occurs.

If a reaction occurs, predict products and If a reaction occurs, predict products and balance….don’t forget phase labels.balance….don’t forget phase labels.

Classify as cationic or anionicClassify as cationic or anionic General form:General form: A + BC A + BC → AC + B (cationic)→ AC + B (cationic)Or Or A + BC → BA + C (anionic)A + BC → BA + C (anionic)

Double ReplacementDouble Replacement

Predict productsPredict productsUse your Solubility Rules (pg 178) to Use your Solubility Rules (pg 178) to

determine whether a reaction occurs.determine whether a reaction occurs. If a reaction occurs, determine phases of If a reaction occurs, determine phases of

productsproductsDetermine the Net ionic equation if asked Determine the Net ionic equation if asked

to do so.to do so.General Form:General Form:AB + CD AB + CD → AD + CB→ AD + CB

From Warm-upFrom Warm-up

1. BaCl2(aq) + H2SO4(aq)

2. C6H12 + O2(g)

3. Zn(s) + CuSO4(aq)

4. K(s) + Br2(g) KBr(s)

5. H2O2(aq) O2(g) + H2O(l)

6. Na(s) + O2(g)

Demo Gas CollectionDemo Gas Collection

In your pairs, the person with the longest In your pairs, the person with the longest eyelashes go get your lab books on the back eyelashes go get your lab books on the back table.table.

Technique for collecting gas via water Technique for collecting gas via water displacementdisplacement

First reactionFirst reactionZinc metal is placed in a jar. Hydrochloric acid is Zinc metal is placed in a jar. Hydrochloric acid is

added to the jaradded to the jarWrite the chemical equation for this reaction and Write the chemical equation for this reaction and

classify it.classify it.

Demo Gas CollectionDemo Gas Collection

Technique for collecting gas via water Technique for collecting gas via water displacementdisplacement

Second reactionSecond reactionHydrogen Peroxide is poured into a jar. A Hydrogen Peroxide is poured into a jar. A

catalyst (NaI) is then put into the jar. catalyst (NaI) is then put into the jar. Hydrogen peroxide then breaks down into Hydrogen peroxide then breaks down into oxygen gas and liquid water.oxygen gas and liquid water.

Write the chemical equation for this reaction Write the chemical equation for this reaction and classify it.and classify it.

On a blank piece of paper…On a blank piece of paper…(5 minutes)(5 minutes)

What gas was formed in reaction #1?What gas was formed in reaction #1?What happened when the burning splint What happened when the burning splint

was placed into the test tube?was placed into the test tube?What gas was formed in reaction #2?What gas was formed in reaction #2?What happened when the glowing splint What happened when the glowing splint

was placed into the test tube?was placed into the test tube?What did you learn from reaction #1?What did you learn from reaction #1?What did you learn from reaction #2?What did you learn from reaction #2?

Demo Demo

Reaction #3Reaction #3 Solid calcium carbonate reacts with hydrochloric Solid calcium carbonate reacts with hydrochloric

acid (HCl)acid (HCl) Write an equation with your reactantsWrite an equation with your reactants Write an If….and…then… statement to test for Write an If….and…then… statement to test for

which gas is produced.which gas is produced. DemoDemo What actually happened?What actually happened? What can you conclude about the gas being What can you conclude about the gas being

produced?produced?

Follow-upFollow-up

Write one thing you learned about Write one thing you learned about chemical equations today.chemical equations today.

Write one thing you still need to know Write one thing you still need to know about chemical equationsabout chemical equations

In pairs…In pairs…

The person with the brightest shirt go get a The person with the brightest shirt go get a white board and dry erase marker.white board and dry erase marker.

Taking turns answer the following Taking turns answer the following questions.questions.

Hold the white board up to show me your Hold the white board up to show me your answer.answer.

Question 1Question 1

Classify the following reactionsClassify the following reactions2NaBr + Ca(OH)2NaBr + Ca(OH)22 CaBr CaBr22 + 2NaOH + 2NaOH

NN22 + 3H + 3H22 2NH 2NH33

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

2NaCl + F2NaCl + F22 2NaF + Cl 2NaF + Cl22

CHCH44 + 2O + 2O22 CO CO22 + 2H + 2H22O O

4P + 10O4P + 10O22 2P 2P22OO55

Question 2Question 2

If a reaction occurs, predict the products If a reaction occurs, predict the products and balanceand balance

FeClFeCl33 + NaOH + NaOH Zn + LiOH Zn + LiOH K + MgBr K + MgBr

Question 3Question 3

Write the net ionic equations Write the net ionic equations NaBr + CaFNaBr + CaF22 FeClFeCl33 + NaOH + NaOH

Ca(NOCa(NO33))22 + Na + Na22SOSO44

Question 4Question 4

Balance Balance

a. __ HgO → __ Hg + __O2

b. __ Fe + __ O2 → __ Fe2O3

c. __ KClO3 → __ KCl + __ O2

d. __ Ca(OH)2 + __ H2SO4 → __H2O + __ CaSO4

e. __ Cu + __ AgNO3 → __ Cu(NO3)2 + __ Ag

f. __ C2H6 + __O2 → __ CO2 + __H2O

Warm-up Warm-up BalanceBalance and and ClassifyClassify the following equation: the following equation:

Mg Mg (s)(s) + CO + CO22 (g)(g) + O + O22 (g)(g) →→ MgCO MgCO33 (s)(s)

For Carbon dioxide, write the following items:For Carbon dioxide, write the following items:Chemical formulaChemical formulaLewis dot structureLewis dot structureVSEPR shapeVSEPR shapePolarity of bondsPolarity of bondsOverall polarity of the moleculeOverall polarity of the molecule

Warm-UpWarm-Up

1. Write a balanced chemical equation for the 1. Write a balanced chemical equation for the following reactionsfollowing reactions

Cu(NHCu(NH33))44SOSO44 → solid Copper(II) sulfate + ammonia gas→ solid Copper(II) sulfate + ammonia gas

Aluminum + Fluorine gas → Aluminum fluorideAluminum + Fluorine gas → Aluminum fluoride

2. Classify these reactions2. Classify these reactions

Warm-up Warm-up

Predict products and classify these reactions

Na2CO3(s)

NH3(g) + H2SO3(aq)

NF3(s)

H2 (g) + O2 (g)

QuizQuiz

Classify the reactionsClassify the reactionsPredict the products (when necessary) Predict the products (when necessary)

and write a balanced chemical equationand write a balanced chemical equationWrite the net ionic equation when Write the net ionic equation when

appropriateappropriateDon’t forget phase labelsDon’t forget phase labels