Reversible Reactions
The product can be turned back into a reactant. It is shown in the symbol ⇌
Examples are: CuSO4 (s) ⋅ 5H2O (l) ⇌ CuSO4 (s) + 5H2O (l)
H2O (l) + CuSO4 (s) ⇌ H2SO4 (s) Copper sulphate ⋅ water ⇌ copper sulphate + water
water + copper sulphate ⇌ sulfuric acid
Heating hydrated copper sulphate
N2 (g) + 3H2 (g) ⇌ 2NH3 (l)
nitrogen + hydrogen ⇌ ammonia Water evaporated blue – white - blue
then condensed
Obtained Extracted and dripped back
from natural from the air down
gas
• The copper ions in its crystal lattice structure
are surrounded by water molecules.
The forward reaction is the one that goes to the right • This water is driven off when blue hydrated
The backward reaction is the one that goes to the left copper sulphate is heated, leaving
white anhydrous copper sulphate.
• Water can then be added back to turn it
back into the blue hydrated copper sulphate.
Dynamic Equilibrium is a reversible reaction that occurs in a closed system so no reactants or products can
escape, and nothing can come in.
- Forward and backward reactions still happen
- The rate of reaction is the same
- Equilibrium is reached when the concentration of reactant = product
Reactant favoured equilibrium à
more reactant than product at DE
(you wouldn’t want this industrailly)
Product favoured equilibrium à more product than reactant at DE (you
can increase the yield by shifting the equilibrium to the right more)
Types of Reactions Precipitation Reaction - formation of an
insoluble salt when two solutions containing
Neutralisation Reaction - acid and a base interact with the soluble salts are combined.
formation of a salt BaNO3 + CaSO4 à BaSO4 + CaNO3
CaO + SiO2 à CaSiO3
Decomposition Reaction - process or effect of
Displacement Reaction - one element is replaced by another in a simplifying a single chemical entity into two or
compound. more fragments
AgNO3 + NaCl à AgCl + NaNO3 MgCO3 à MgO + CO2
Salt-dissolving Reaction - salt dissolves, the ionic bonds between Combustion Reaction - oxygen reacts with
the atoms break. another substance and gives off heat and light
NaCl à Na+ + Cl- CH4 + O2 → CO2 + H2O