Chemical reactions involve substances undergoing fundamental changes in identity, with reactants being used up and products being formed. Two key examples are cell respiration, where glucose and oxygen react to produce carbon dioxide, water, and energy, and photosynthesis, where carbon dioxide, water, and light energy are used to produce glucose and oxygen. Chemical reactions are represented by balanced chemical equations that show the reactants and products. There are several types of chemical reactions including synthesis, decomposition, single displacement, double displacement, and combustion.

1. Chemical reactions
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3. Chemical reactions
• Chemical reaction occurs when substances
undergo fundamental changes in identity; one
or more substance are used up while one or
more substance are formed.
• C6H12O6 + O2 ------ CO2 + H2O + Energy
cell respiration
• CO2 + H2O + light ---------- C6H12O6 + O2
photosynthesis

4. Chemical reactions
• Chemical reaction
– Starting material Reactants.
– Substance produced by the reactions are called
products.
• Chemical equations are used to represent,
symbollically, what is taking place during the
reaction
– Example:
C6H12O6 + O2 ------ CO2 + H2O + Energy

5. Chemical reactions
Reactants + Reactants Product
(Yields)
C6H12O6 + O2 CO2 + H2O

6. Balanced chemical equations
Mg + O2 MgO
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7. Classifying reactions
• Combination (synthesis) Reaction
• Decomposition Reaction
• Single-Replacement Reaction
• Double-Replacement Reaction
• Combustion Reaction

8. TYPE OF REACTIONS
1. SYNTHESIS or ADITION: A + B AB
2. DECOMPOSITION OR ANALYSIS : AB A + B
ENERGY
HCl + NH3 NH4Cl
CaCO3 CaO + CO2
HEAT

9. TYPE OF REACTIONS
3. SIMPLE displacement: A + BC AC + B
4. DOBLE displacement: AB + CD AD + CB
Cu + H2O H2 + CuO
NaCl + AgNO3 NaNO3 + AgCl

10. TYPE OF REACTIONS
5. COMBUSTION
CH4 + 2O2 CO2 + 2H2O + CALOR