Chemical reactions. (Chapter 5)

the input of energy, into two or more elements or simpler compounds.
Decomposition reactions can be illustrated;
AB → A + B

2. Decomposition (Analysis) Reactions

Types of Chemical Reactions
According to number of reactant and product:

and displaces another element from the compound.
Displacement reactions can be illustrated;
A + BC → B + AC

3. Single Displacement Reactions

Types of Chemical Reactions
According to number of reactant and product:

Single displacement reactions mostly take place due to activity differences of elements. A more active element displaces a less active one.

Zn(s) + CuSO4(aq) → Cu(s) + ZnSO4(aq)
Fe(s) + NaCl(aq) → No reaction

+ Cl2(g) → 2NaCl(aq) + Br2(g)
Ca(s) + 2H2O → Ca(OH)2(aq) + H2(g)
Mg(s) + 2CuCl(aq) → MgCl2(aq) + 2Cu(s)

exchange ions and form two new compounds.
One of the products must be a solid precipitate, a gas, or a molecular compound, such as water.
Double displacement reactions can be illustrated;
AB + CD → AD + CB

4. Double Displacement (Metathesis) Reactions

Types of Chemical Reactions
According to number of reactant and product:

Some examples;
HCl(aq) + NaOH(aq) → HOH(l) + NaCl(aq)
Pb(NO3)2(aq) + K2CrO4(aq) → PbCrO4(ppt) + 2KNO3(aq)

energy is exothermic reaction.

Endothermic and Exothermic Reactions

Types of Chemical Reactions
According to heat:

Some examples;
Ca(s) + 2H2O(l) → Ca(OH)2(aq) + H2(g) + Energy
Exothermic Reaction
H2O(l) + Energy → H2(g) + O2(g)
Endothermic Reaction

are in same state.
 N2(g) + H2(g) → NH3(g)
2. Heterogenous reactions: States are different.
Fe(s) + CuCl2(aq) → FeCl2(aq) + Cu(s)
Na(s) + C2H5OH(aq) →C2H5ONa(aq)+H2(g)