predicting products (aka: soap opera chemistry). why are we learning this? chemistry standard #3a:...

Predicting Products

(AKA: Soap opera Chemistry)

Why are we learning this?

Chemistry Standard #3A:

Students know how to describe and balance chemical reactions

Five types of reactions:1.Synthesis (Combination)2.Decomposition3.Single Replacement4.Double Replacement5.Combustion

1. Synthesis (or Combination)

2 or more substances react to form 1 product

A + B AB

The soap opera begins . . .

+

Rob + Sally Rob/Sally

Demo #1: Synthesis Reaction

Mg(s) + O2(g) MgO(s)

Remember to balance the equation!

2 2

2. Decomposition

A compound breaks down into simpler substances.

-requires heat, light, electricity, or a chemical catalyst

AB A + B

Drama with Rob and Sally . . .

+ Sally

+

Rob/Sally Rob

Demo #2: Decomposition Reaction

_C12H22O11+_ KNO3(s)

Remember to balance the equation!

__CO2 (g) + __H2 O(g)

3. Single Replacement Reaction

Atoms in single element replace atoms in compounds

• Can be cationic or anionic . . .– A metal replaces the cation in the compound– A nonmetal replaces the anion in the compound

Cationic SR: A is a metal element, B is cation (+)

A +BC AC + B Anionic SR: C is a non-metal element, D is anion (-)

C + BD BC + D

How can you know if one metal will displace another?

reactive metal replaces any below it.

Will this React? Mg + ZnCl2

Will this React? Mg + CaCl2

Li

K

Ca

Na

Mg

Al

Zn

…

MgCl2 + Zn

YES !

NR

Along comes Brian . . .

Brian

+ +

+ Rob/Sally Brian/Sally + Rob

Demo #3: Single Replacement Reaction

Cu(s) + AgNO3(aq) Ag(s)+ CuNO3(aq)

Cu(s) + AgNO3(aq) Ag(s) + CuNO3(aq)

Mg(s) + CuNO3(aq) Cu(s) + Mg(NO3)(aq)

Grey blue aqueous reddish clear aqueous

metal solution metal solution

4. Double Replacement Reaction

Compounds exchange cations

AB + CD CB + AD

Drama at the prom . . .

+ +

+ Brian/Sally Rob/Pam Brian/Pam + Rob/Sally

Demo #5: Double Replacement Reaction

Cu(NO3)2(aq)+ NaOH(aq) Cu(OH)2(aq) + NaNO3

Remember to balance the equation!

2 2

An element/compound reacts with O2 producing heat &/or light.

Example: Mg(s) + O2(g) MgO(s)

with hydrocarbons yielding CO2 and H2O

Example: C3H8 + O2 CO2 + H2O

5. Combustion

The Soap opera Ends

Brian + O2 CO2 + H2O

Oh No!(A hydrocarbon)

Demo#6: Combustion

__C3H7OH + __O2 __CO2 + __ H2O

Propanol  

Remember to balance the equation!

Six types of chemical reaction

CombustionSynthesisDecompositionSingle DisplacementDouble DisplacementAcid-base