How do chemists know what to mix together to make the products they

want???

Substances react with one another in similar ways depending on their chemical makeup and driving forces of different situations.

Combination (or Synthesis)when two or more substances react to form one product

A + Z AZ

Types: Synthesis

Example C + O2

OO C + O O C

OO COO C OO C OO C OO

CO

O C

OO

CO

O

C O

O

C O

O

C OO

C OO C

OO C OO C

General: A + B AB

Practice: determine how the following substances combine to form a new more

complex compound and then BALANCE

Mg(s) + O2 (g) ???

Na(s) + Cl2 (g) ???

Zn (s) + S (s) ???

Zn (s) + I2 (s) ???

Decomposition RxNs

When a complex compound undergoes a reaction and breaks apart to produce two or more other (more simpler) substances

– (heat or light may be used to do this)

AZ A + Z

Types: Decomposition

Example: NaCl

General: AB A + B

Cl Na Cl + Na

Types: Decomposition

Example 2HgO

O Hg

O Hg

Hg

O O Hg

+

General: AB A + B

Decomposition of Metal Hydrogen Carbonate

Compounds

When a metal hydrogen carbonate, upon heating, will breaks down to yield a metal carbonate compound, water and carbon dioxide

2NaHCO3 (s) Na2CO3 (s) + H2O(g) + CO2 (g)

The delta (triangle) in the equation means that heat is applied

Decomposition of Metal Carbonate Compounds

When a metal carbonate, after prolonged heating, breaks down to yield a metal oxide compound and carbon dioxide

CaCO3 (s) CaO (s) + CO2 (g)

Decomposition of Chlorate Compounds

A chlorate will break down to yield its binary salt and oxygen gas.

KClO3 (s) KCl (s) + O2 (g)

Practice: determine how each complex compound will break down into simpler

substances and then BALANCE NO2 ???

CaCO3 ???

KHCO3 ???

H2O ???

Combustion• Rapid reaction that produces a flame

• Involves O2 from the air as a reactant

C3H8 (g) + O2 (g) CO2 (g) + H2O (g)

– C3H8 is common propane from your gas grill

– This is the complete combustion of propane

• Hydrocarbons are compounds that contain ONLY carbon and hydrogen

• Complete combustion of hydrocarbons in oxygen produces ONLY water and carbon dioxide

Practice: determine the products of these complete combustion reactions

and then BALANCE

C6H12 + O2 ???

CH4 + O2 ???

C4H8 + O2 ???

Single Displacement RxNsWhen one more reactive metal (as per the activity series) displaces another less active metal (or hydrogen) from a compound or solution

A(s) + BZ AZ + B(s)

Types: Single displacement

Example: Zn + CuCl2

ZnClCl Cu +

General: AB + C AC + B

ClCl Zn Cu+

Activity Series

Foiled again –Foiled again –Aluminum loses to CopperAluminum loses to Copper

Element Reactivity

LiKBaSrCaNaMgAlMnZnCrFeCoNiSnPbH2

CuAgHgPtAu

Halogen Reactivity

F2

Cl2Br2

I2

More A

ctiveLess A

ctive

How to determine if a single replacement reaction will occur…

when Mg (s) + CoSO4 (aq) ?

1) Find both metals (Mg & Co) on activity series2) If lone metal (Mg) is higher up on activity series than the

metal in the compound (Co)…Mg is more reactive thus it will take Co’s position and replace it in the compound

3) If Mg is not more reactive…then No Reaction occurs…

– HERE…Mg is higher up on the activity series so it is more reactive than Co …THUS the reaction WILL occur

Mg(s) + CoSO4 (aq) MgSO4 (aq) + Co(s)

Types of Reactions

Practice (determine if a reaction will occur, if a reaction occurs then predict the products and balance if necessary))

• Zn(s) + HBr (aq)

• Mg(s) + H2O (l)

• Cd(s) + HNO3 (aq)

• Al (s) + H2SO4 (aq)

3. Single Replacement Reactions3. Single Replacement Reactions• Single Replacement Reactions Single Replacement Reactions occur occur

when one element replaces another in a when one element replaces another in a compound.compound.

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

• element + compoundelement + compound product + product product + product A + BC A + BC AC + B AC + B (if A is a metal)(if A is a metal) ORORA + BC A + BC BA + C BA + C (if A is a nonmetal)(if A is a nonmetal)

(remember the cation always goes first!)(remember the cation always goes first!)

When HWhen H22O splits into ions, it splits intoO splits into ions, it splits intoHH++ and OH and OH-- (not H+ and O (not H+ and O-2-2 !!) !!)

4. Double Replacement Reactions4. Double Replacement Reactions

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

• Compound + compound Compound + compound product + product + productproduct

• AB + CD AB + CD AD + CB AD + CB

Double Replacement ReactionsDouble Replacement Reactions

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

• Example:Example:

AgNOAgNO3(aq) 3(aq) + NaCl+ NaCl(s) (s) AgCl AgCl(s) (s) + NaNO+ NaNO3(aq)3(aq)

• Another example:Another example:

KK22SOSO4(aq) 4(aq) + Ba(NO+ Ba(NO33))2(aq) 2(aq) KNO KNO3(aq)3(aq) + + BaSOBaSO4(s) 4(s)

2

PracticePractice

• Predict the products. Balance the Predict the products. Balance the equationequation

1.1. HClHCl(aq)(aq) + AgNO + AgNO3(aq) 3(aq)

2.2. CaClCaCl2(aq) 2(aq) + Na+ Na33POPO4(aq) 4(aq)

3.3. Pb(NOPb(NO33))2(aq) 2(aq) + BaCl+ BaCl2(aq) 2(aq)

4.4. FeClFeCl3(aq) 3(aq) + NaOH+ NaOH(aq) (aq)

5.5. HH22SOSO4(aq)4(aq) + NaOH + NaOH(aq)(aq)

6.6. KOHKOH(aq)(aq) + CuSO + CuSO4(aq) 4(aq)

Will a compound dissolve in water?• A compound that DOES dissolve in water its called soluble

• A compound that DOES NOT dissolve in water its called insoluble

1) Write the formula of the following compounds

2) Predict if each compound will dissolve in water

• Sodium chloride• Barium acetate• Potassium sulfate• Calcium phosphate

3) Use your solubility guidelines to check to see if you “guessed” correctly ((find the anion on the left side of the table and determine if it IS or IS NOT soluble…then check the exceptions to each on the right side of the table))

Precipitation (exchange or metathesis)

When two soluble compounds exchange ions (replace OR displace one another) in order to form at least one insoluble product (this is insoluble and falls out of solution as a precipitate)

AX + BZ AZ + BX• either AZ or BX MUST be a precipitate if no precipitate forms then no reaction occurs

Will a precipitate form?

Use Your Solubility Guidelines:1) Note the individual ions present2) Consider how each ion could “switch partners” to

form new combinations3) Use the guidelines to determine ((find the anion on the left

side of the table and determined if it is OR is not soluble…then check the exceptions to each on the right side of the table))

if the new combinations of “switched partners” are insoluble (do not dissolve in water)

4) The insoluble possibility will force the reaction to occur by forming a precipitate and falling out of solution

Will a precipitate form…

when solutions of Mg(NO3)2 and NaOH are mixed?

• All are aqueous so you have ions Mg+2 & NO3- ; Na+ & OH-

• Possible interacts are Mg+2 OH- and Na+ NO3-

• Checking solubility guidelines…most hydroxides (OH’s) are insoluble and Mg(OH)2 is NOT an exception the reaction occurs as

Mg(NO3)2 (aq) + 2NaOH (aq) Mg(OH)2 (s) + 2NaNO3 (aq)

Practice: determine if a reaction occurs; if yes, then predict the products and balance the equationMgSO4(aq) + BaCl2(aq) ???

AlBr3(aq) + Na2Cl2(aq) ???

AgC2H3O2 (aq) + SrI2(aq) ???

FeSO4(aq) + Ca(OH) 2(aq) ???

Ionic EquationsShows ions completely dissolved in water (strong electrolytes) as

ions in the chemical equation

Mg(NO3)2 (aq) + 2NaOH (aq) Mg(OH)2 (s) + 2NaNO3 (aq)

• Equation showing chemical formulas only is called molecular equation

Mg+2(aq) + 2(NO3)-(aq) + 2Na+(aq) + 2 OH-(aq) Mg(OH)2 (s) + 2Na+(aq) + 2NO3- (aq)

• Equation showing ALL IONS PRESENT (as ions) is called complete ionic equation

Mg+2(aq) + 2 OH- (aq) Mg(OH)2 (s)

• Equation showing ONLY IONS THAT TAKE PART IN REACTION (as ions) is called NET ionic equation

• Ions that do not take part in reaction (appear in identical forms on both sides) are called spectator ions

If every ion in a complete ionic equation is a spectator, then NO reaction occurs!!!

Practice

Write the complete ionic reaction for

AgC2H3O2 (aq) + SrI2(aq) ???

AND THEN Write the corresponding net ionic reaction

PracticeWrite the complete ionic reaction for

FeSO4(aq) + Ca(OH) 2(aq) ???

AND THEN Write the corresponding net ionic reaction