Warm Up: Why do chemical equations need to be

balanced?

Balance the following equation:

__PbCl2 + __ AgNO3 __Pb(NO3) + __ AgCl

Types of Chemical Reactions

Learning Target: To be able to identify the different type of reactions when looking at skeletal equations

Types of Reactions:

There are 5 types of Reactions:1. Synthesis2. Decomposition3. Single-replacement4. Double-replacement5. Combustion

Synthesis: A chemical rxn in which 2 or more substances (A + B) react to produce a single product (AB)

A + B ⇒ ABNa(s) + Cl2(g) ⇒ NaCl(s)

SO2(g) + O2(g) ⇒ SO3(g)

Decomposition: A rxn in which a single compound (AB) breaks down into 2 or more new substances (A + B…)

AB ⇒ A + B

NH4NO3(s) ⇒ N2O(g) + H2O(g)

Na3N(s) ⇒ Na(s) + N2(g)

Single Replacement: A rxn in which the atoms of one element replace the atoms of another element in a compound

A + BX ⇒ AX + B

Li(s) + H2O(l) ⇒ LiOH(aq) + H2(g)

Cu(s) + AgNO3(aq) ⇒ Ag(s) + Cu(NO3)2

Double Replacement: a rxn which involves an exchange of ions between 2 compounds

AX + BY ⇒ AY + BX*Either the metals change places or the nonmetals change places but not both!!!

Ca(OH)2(aq) + HCl(aq) ⇒ CaCl2(aq) + H2O(l)

*Typically occurs in aqueous solutions (in water)

NaOH(aq) + CuCl2(aq) ⇒ NaCl(aq) + Cu(OH)2(s)

*Precipitate: Is when a solid forms from a solution

3 Types of Double Replacement:

1.Formation of a precipitate

2.Formation of H2O

3.Formation of a product which decomposes into a gas

Double-Replacement: Formation of a precipitate

Solubility Rules: Some compounds will dissolve in water (soluble) Some will NOT dissolve in water (insoluble/ not

soluble)

If during a double-replacement rxn is formed, it will fall out of the solution as a solid, which is called a percipitant.

Double-Replacement: Formation of H2O These occur between Acids and Bases

Acids ALWAYS start with _________ Bases are compounds that end with hydroxides

(OH-) One product will be H2O and one will be an ionic

compound salt

HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)

*Some people consider this a separate rxn altogether

Combustion: a rxn in which O2 can combine with a substance to release energy Ex: Fire, Burning, Magnesium Stripe, etc.

C(s) + O2(g) ⇒ CO2(g)

CH4(g) + O2(g) ⇒ CO2(g) + H2O(l)

*In most cases, the products will be H2O and CO2

Activity Series: Single Replacement Rxn

Active metals will replace less active metals in reactions.

Pt(s) + Zn2O (aq) → NR

Fe(s)  +  CuSO4(aq)  →    FeSO4(aq)  +  Cu(s)

Na(s) + SnCO3(aq) → Na2CO3(aq) + Sn(s)

Practice Problems: Complete these in your notes and see how many you get right!

1. C2H6(g) + O2(g) → H2O(g) +CO2(g)

2. Br2(l) + LiI(s) → LiBr + I2(s)

3. Fe(s) + H2O(l) →Fe3O4(s) + H2(g)

4. MgCO3(s) → MgO(s) + CO2(g)

5. P4(s) + O2(g) → P4O10(s)

6. KNO3(s) → KNO2(s) + O2(g)

7. KOH + H3PO4 →K3PO4 + H2O

8. Na(s) + O2(g) →Na2O(s)

9. O2(g) + C6H12O6(g) → H2O(g) + CO2(g)