1. Topic: Chemical Reactions
Do Now:

2. Physical vs. Chemical Change
Physical Change =
Chemical Change =
Change in form/appearance
Examples:
Dissolving & phase changes
Change in identity
Change in formula representing
a substance

3. Evidence of a Chemical Reaction
Temperature change
Emission of Light Energy
Change in identifying property:
Color, mp, bp, density, Hf, Hv, c …
Formation of Gas
Bubbling, odor
Formation of Solid
Precipitate

4. Chemical Equations A + B  C + D
Left Side = Reactants (starting materials)
Right Side = Products (ending materials)
“” is read as produces/yields
How do we show the physical state of the reactants & products?
(s), (l), (g), (aq)

5. Types of Reactions Synthesis Decomposition Single Replacement
Double Replacement
Combustion

6. Synthesis Format: A + B  C Identifying feature: 1 product only
Note: A and B may be elements or compounds,
C is a compound
2 Fe(s) Cl2(g)  2 FeCl3(s)
CaO(s) + H2O(l)  Ca(OH)2(s)

7. Decomposition Format: AB  A + B Identifying feature: 1 reactant only
Note: A & B may be elements or compounds
2 NaN3(s)  2 Na(s) N2(g)
NH4NO3(s)  N2O(g) H2O(g)

8. Single Replacement Format: A + BX  AX + B Identifying Feature:
Element + Compound 
Different Element + Different Compound
2 Li(s) H2O(l)  2 LiOH(aq) + H2(g)
Cu(s) + 2AgNO3(aq)  2Ag(s) + Cu(NO3)2(aq)

9. Double Replacement Format:AX + BY  AY + BX Identifying feature:
2 compounds yield 2 new compounds
Ca(OH)2(aq) + 2HCl(aq)  CaCl2(aq) +
2 H2O(l)
2 NaOH(aq) + CuCl2(aq)  2 NaCl(aq) +
Cu(OH)2(s)

10. Combustion or Reaction with O2
Format: A + O2  B ( + C + …)
Identifying feature: One of reactants is O2
Note: A can be an element or a compound,
usually more than 1 product
CH4(g) O2(g)  CO2(g) H2O(g)
For Regents synthesis TOPS combustion:
2 H2(g) + O2(g)  2 H2O(g)
C(s) + O2(g)  CO2(g)

11. Identify the Reaction Type
CaO + CO2  CaCO3
2 H2O  2 H2 + O2
NaOH + HCl  NaCl + H2O
Zn HCl  ZnCl2 + H2
2 Mg + O2  2 MgO
Mg + H2SO4  MgSO4 + H2
2 KClO3  2 KCl O2
AgNO3 + NaCl  NaNO3 + AgCl
C2H6 + O2  CO2 + H2O
Synthesis
Decomposition DR SR
Synthesis SR
Decomposition DR
Combustion