1. Types Of Chemical Reactions

2. Objective Distinguish between the 5 different types of reactions
Predict the products of a reaction
Predict the physical states of products

3. 5 Types of Reactions Composition/Synthesis Decomposition
Single Replacement
Double Replacement
Combustion

4. Composition Reactions aka synthesis rxn
When two or more substances react to form a single product
2 reactants → 1 product
A + X → AX
H2 + O2 →
MgO + CO2 →
2 H2O
MgCO3

5. Decomposition
Occurs when a compound is broken down into simpler substances
Single reactant yields two or more products
(1 reactant → 2 products)
forms a common gas as one of the products; CO2, O2, SO2, H2O

6. Decomposition Examples
AX → A+ X
HgO →
CaCO3 →
Hg + O2
CaO + CO2

7. Single Replacement One substance replaces another
A metal replaces a metal, if it is more active
A non-metal replaces a non-metal, if it is more active

8. Single Replacement Examples
A and B are metals; X and Y are non-metals
A + BX → AX + B OR Y + BX → BY + X
Mg + Zn(NO3)2 →
Cl2 + KBr →
Mg (NO3)2 + Zn
KCl + Br2

9. Double Replacement An exchange of partners
The metal replaces the metal and the non-metal replaces the non-metal
AX + BY → AY + BX
Na2S + Cd(NO3)2 →
BaCl2 + K2CO3 →
NaNO3 + CdS
BaCO3 + KCl

10. Composition A + X → Fe + O2 → H2O + SO3 → AX FeO H2 SO4
Two elements or compounds combine to form a single substance
A + X →
Fe + O2 →
H2O + SO3 → AX
FeO
H2 SO4

11. 5 Kinds of Decomposition Reactions
Metallic Carbonates
Metallic Hydroxides
Metallic Chlorates
Oxy Acids
Oxides

12. Metallic Carbonates CaCO3 → Metal oxide and carbon dioxide formed
CaO + CO2

13. Metallic Hydroxides
Many metallic hydroxides (OH-), when heated, decompose into metallic oxides and water.
Ca(OH)2 →
Metal oxide and water formed
Exceptions to the rule: NaOH and KOH
CaO + H20

14. Metallic Chlorates
(ClO3-), when heated, decompose into metallic chlorides and oxygen
2KClO3 →
metal chloride and oxygen formed
2KCl + 3O2

15. Oxy Acids
Some oxy acids, when heated, decompose into nonmetallic oxides and water
Seltzer Water
H2CO3 →
Acid Rain
H2SO3 →
CO H2O
SO2 + H2O

16. Oxides Some oxides, when heated, decompose. 2HgO → 2Pb O2 → 2Hg + O2
2PbO + O2

17. 4 Kinds of Single Replacement Reactions
Metal w/ more active metal
Hydrogen in acids w/ more active metal
Hydrogen in water w/ by most active metals
Halogen w/ more active halogen

18. Metal w/ more active Metal
Replacement of a metal in a compound by a more active metal (PCS Mazintl)
Zn + CuSO4 →
Zinc replaces the copper, therefore zinc is more active
ZnSO4 + Cu (s)

19. Hydrogen in acids w/ more active metals
Replacement of hydrogen, in acids, by metals more active than hydrogen (PCS Mazintl)
Zn + H2SO4 →
The corresponding metallic compound and hydrogen gas are formed
Zn SO4 + H2 (g)

20. Hydrogen in water w/ most active metals
Replacement of hydrogen, in water, by the most active metals. Which Metals?
All Group I and some of Group II
Ca + 2 H2O →
A hydroxide and hydrogen gas are formed
Ca(OH)2 + H2 (g)

21. Halogen w/ more active halogen
Replacement of a halogen by a more active halogen
Cl2 + 2 KBr →
Br2 + 2 KI →
MgBr2 + I2 →
The corresponding metallic compound and elemental halogen are formed
2 KCl + Br2
2 KBr + I2
no reaction because Br is more active than I, so I will not replace Br

22. Activity Series of the elements
A + BX → AX + B
If A replaces B, then A is more active than B
If an element is above another element on the chart, then it is more active, and will replace the lower positioned element
All metals above hydrogen displace hydrogen from hydrochloric acid or dilute sulfuric acid.

23. More Active P.C.S. Mazintl Activity of Halogens P potassium Fluorine
C calcium Chlorine
S sodium Bromine
M magnesium Iodine
a aluminum
z zinc
i iron
n nickel
t tin
l lead
HYDROGEN
Copper
Mercury
Silver
More Active

24. Example
Zn (s) + CuSO4 (aq)→

25. More Active P.C.S. Mazintl Activity of Halogens P potassium Fluorine
C calcium Chlorine
S sodium Bromine
M magnesium Iodine
a aluminum
z zinc
i iron
n nickel
t tin
l lead
HYDROGEN
Copper
Mercury
Silver
More Active

26. Example Zn (s) + CuSO4 (aq)→ ZnSO4 (aq) + Cu (s)
Mg (s) + Zn(NO3)2 (aq) →
ZnSO4 (aq) + Cu (s)
Mg (NO3)2 (aq) + Zn (s)

27. Double Replacement AX + BY → AY + BX
usually takes place in a solution of water…all reactant solutions are aqueous
2 compounds → 2 different compounds
1 of these will not be soluble in water…solid (s)
The soluble (dissolved) compound is aqueous…(aq)
In order for you to know if the reaction has occurred, a solid or gas must form
1 product will typically be:
solid: precipitate
gas: CO2 SO2 NH3

28. Solubility Rules for Double Dis(RE)placement Reactions
How to determine which product is the precipitate
Na+ K+
NH4+
NO3- [
Will always be soluble in water.
Tells you what won’t precipitate, so assume the other one will

29. Examples CaCO3 + 2 HCl → Pb(NO3)2 + KI → NaOH + KI → → CaCl2 + H2CO3
H2O + CO2
PbI KNO3
no reaction because both products are soluble
NaI + KOH

30. Combustion An element or compound reacts with oxygen
Usually produces heat → Exothermic
Combustion of a hydrocarbon always produces carbon dioxide and water
2 Mg + O2 →
2 CH3OH + 3 O2 →
2 MgO + heat
2 CO2 + 4 H20 + heat

31. Writing Molecular, Complete Ionic, and Net Ionic Equations
Molecular Equations: an equation showing the complete neutral formulas for every compound in the reaction.
AgNO3 (aq) + NaCl (aq)→ AgCl(s) + NaNO3 (aq)

32. Complete Ionic Equation of :
Complete Ionic Equations: equations that show reactants and products as they are actually present in solution.
Ionic compounds dissociate (dissolve) in water, so they are written as individual ions…if the compound is soluble…check your solubility rules
Complete Ionic Equation of :
AgNO3 (aq) + NaCl (aq)→ AgCl(s) + NaNO3 (aq)

33. Spectator Ions: ions in solution that appear unchanged on both sides of the equation
Net Ionic Equation: equations which show only the species that actually participate in the reaction
Spectator ions are omitted from the net ionic equation

34. Write the Net Ionic Equation for: Ag+ (aq) + NO3- (aq) + Na+ (aq) + Cl- (aq) → AgCl(s) + Na+ (aq) + NO3-(aq)

35. Write the molecular, complete ionic and net ionic equations for the following: lead (II) nitrate reacts with lithium chloride.

36. Write the molecular, complete ionic and net ionic equations for the following: Hydrobromic acid reacts with calcium hydroxide

37. END