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 simple substances

combine to form one product

A + Z AZ

C + O2 CO2

Pg 284

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 breaks down into two or more simpler substances

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

AZ A + ZPg 286

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

substances and then BALANCE NO2 ???

H2O ???

KCl ???

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 (& O)

• Complete combustion of hydrocarbons in oxygen produces ONLY water and carbon dioxide Pg 285

Practice: determine the products of these complete combustion reactions

and then BALANCE

C6H12 + O2 ???

CH4 + O2 ???

C4H8 + O2 ???

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

A(s) + BZ AZ + B(s)Pg 287-289

Activity SeriesElement Reactivity

LiKBaSrCaNaMgAlMnZnCrFeCoNiSnPbH2

CuAgHgPtAu

Halogen Reactivity

F2

Cl2Br2

I2

More A

ctiveLess A

ctive

How to determine if a single replacement reaction will occur…

1) Find both metals on activity series2) If LONE metal is higher up on activity series

than the metal in the compound…the LONE metal more reactive

3) If the LONE metal is more reactive…it will take the position of the other metal within the compound

3) If the LONE metal is less 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)

And then balance

Determine if a reaction will occur for:

Mg (s) + CoSO4 (aq) ?

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)

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

Will a compound dissolve in water?1) Write the formula of the following compounds2) Predict if each compound will dissolve in water

• Sodium chloride• Barium acetate• Potassium sulfate• Calcium phosphate3) 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 Reaction(exchange or metathesis)

When two soluble compounds “switch” ions to form at least one insoluble product that will fall 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

Pg 290-291

Will a precipitate form?Use Your Solubility Guidelines:

1) Note the individual ions present

2) Consider how each ion could “switch partners” to form new combinations

3) Use the guidelines to determine if new combos are insoluble

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) ???