Predicting Products of a Reaction

Will a reaction take place?If so, what will be produced?

Predicting Products

• NOT just a shot in the dark!

• Rules govern whether or not reactants will form new products.

Predicting Single Replacement Reaction

1. Decide which element is a metal and nonmetal. Decide which part is positive and negative.

+2 +1 +2 +1-1 -1METAL METAL METAL METALNON NON

Predicting Single Replacement• 2. USE ACTIVITY SERIES CHART from reference table to

see if loner metal is higher than metal in compound.

• If YES the reaction proceeds, higher metal displaces

the lower metal

• If NO the reaction will not occur. No RXN!

• Examine Activity Series of Metals • Examine Activity Series of Halogens

HIGHER REPLACES LOWER!

Activity Series of Halogens

HIGHER REPLACES LOWER

Predicting Single Replacement

• 3. Higher REPLACES lower

• metal replaces metal

• halogen replaces halogen

Predicting Single Replacement4. Write correct formulas for new products! • Remember ionic compounds (criss x cross)• Remember diatomic gases (Br2 I2 N2 Cl2 H2 O2 F2)

Predicting Single Replacement5. BALANCE EQUATION by balancing coefficients.

EXAMPLE

Fe + HCl

Iron (Fe) will try to replace the hydrogen (H) in HCl.

Can Iron (Fe) replace the hydrogen (H) in HCl? Check Activity Series! Is Fe higher than H? YES

Iron (Fe) replaces the hydrogen (H) in HCl and bonds with chloride (Cl) bumping out (H) from the compound.

FeCl3 + H2

Final Step is ALWAYS BALANCE!

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Predicting Double Replacement

1. Divide molecules into + and - halves. • Positive halves switch partners!

Predicting Double Replacement

2. Write correct formula for new molecules on product side by criss x crossing charges.

NaOH (aq) + CaSO4 (aq)

+1 -1 +2 -2

Na2SO4 + Ca(OH)2

+1 -2 +2 -1

Predicting Double Replacement

3. Balance the EQUATION!

NaOH (aq) + CaSO4 (aq) Na2SO4 + Ca(OH)22

Predicting Double Replacement4. Decide which product will be a solid and which will be

aqueous. Watch this http://phet.colorado.edu/en/simulations/category/chemistry

• USE SOLUBILITY RULES! Reference Table• (s) INSOLUBLE does not dissolve in water, ppt

• (aq) SOLUBLE dissolves in water

(aq) (s) 2 NaOH (aq) + CaSO4 (aq) Na2SO4 + Ca(OH)2

Predicting Double Replacement5. IF both products are aqueous, then no reaction

occurs.