1. Types of chemical
reaction
Sir Naimat ullah

2.  a process that involves rearrangement of the
molecular or ionic structure of a substance, as
distinct from a change in physical form or a
nuclear reaction.
 OR
 (Chemistry) a process that involves changes
in the structure and energy content of atoms,
molecules, or ions but not their nuclei.

3. Five Types of Chemical Reactions:
1. Combustion
3. Decomposition
4. Single Displacement
5. Double Displacement
2. Synthesis

4.  Colour / Odour Change
Formation of a gas or solid
Difficult to reverse
Release/Absorption of Energy (heat)

5. More commonly known as burning
Easily identified (release of heat)
HeatFuel
For combustion 3 things need to be present:
Oxygen

6. Sulphur (in gasoline):
S(s) + O2(g) SO2(g) + Heat
2 H2(l) + O2(l) 2 H2O(g) + Heat
Rocket Fuel:

7. Combustion Situation
Element in
Reactant
Common
Oxide
Coal in a coal-fired electricity generator carbon CO2 (g)
Burning of rocket fuel Hydrogen H2O (g)
Commercial production of sulphuric acid Sulphur SO2 (g)
Lightning strikes and volcanoes Nitrogren NO2 (g)

8.  combination of two or more simple substances
combining to form a more complex substance.
A + B AB
+

9. 22
Synthesis of Magnesium Oxide

10. C(s) + O2(g) CO2(g)
S(s) + O2(g) SO2(g)
 Synthesis Reactions:

11.  Breaking down large, complex molecules or ionic
compounds into smaller, simpler entities.
AB A + B
+

12. Decomposition of Hydrogen PeroxideDecomposition of Hydrogen Peroxide
2 2

13.  reaction of an element with a compound that
produces a new element and new compound.
A + BC AC + B

14. HClHCl(aq)(aq) + Zn+ Zn(s)(s)  HH2(g)2(g) + ZnCl+ ZnCl2(aq)2(aq)2

15.  SOLUTE – is a pure substance
(usually lesser in quantity) that is
dissolved in another pure
substance called the “SOLVENT”
 AQUEOUS SOLUTION – a
solution in which water is the
solvent (aqua – meaning water).

16.  Solutions are homogenous mixtures of solutes
and solvents.
 Solubility is the measure of how much of the
solute can possibly dissolve in a known amount of
solvent. If a substance has high solubility in water,
it has a subscript of (aq). However, if it isn’t very
soluble it will start to precipitate out and will have a
(s) subscript for solid.

17.  Is calcium hydroxide soluble?
 Is sodium flouride soluble?
 What about lead (II) Iodide?

18.  reaction of two compounds, where the positive and negative ions
in their respective compounds switch places to form two new
compounds. This can only happen with ionic compounds
AB + CD AD + CB

19. A double displacement reaction only occurs if one of the
following three results are seen:
 a precipitate is formed
 a gas is produced
 a change of pH occurs (a neutralization reaction)
** If the products are both soluble then the reaction is
NR (no reaction)

20. Pb(NOPb(NO33))2(aq)2(aq) + KI+ KI(aq)(aq)  PbIPbI2(s)2(s) + KNO+ KNO3(aq)3(aq)22
Precipitate: A solid
that is formed as a
result of the chemical
reaction of two
aqueous solutions.

21.  FeCl3(aq) + Na2(SO4)2(aq) → ?
NR – both are soluble
 HCl(aq) + LiOH(aq) → ?
pH change – neutralization reaction, products are LiCl & H2O
 2HNO3(aq)+ K2CO3(aq)→ CO2(g)+H2O(l) + 2 KNO3(aq)
gas produced – therefore double displacement

22. Compositio
n of
Common
Alloys
Alloy % Composition Property
Brass Cu (70%)
Zn (30%)
Harder and more
resistant to corrosion
than copper
Stainless
Steel
Fe (80%)
Cr (18%)
Ni (1%)
Si (1%)
More resistant to
corrosion then iron
18K gold Au (75%)
Ag (13%)
Cu (12%)
Harder and less
malleable than 24K
gold

23.  Percentages are calculated by weight
How much gold (in grams) is there in 10g sample of 18K
yellow gold where the % composition is 75% Au?
Answer: mass of Au= (75% / 100) x 10g
= 7.5 g
Therefore there is 7.5 g of pure gold in a 10g sample of
18K yellow gold.