UNIT 1 :STRUCTURE, BONDING AND
INTRODUCTION TO ORGANIC CHEMISTRY
TOPIC 1 – FORMULAE, EQUATIONS AND AMOUNT OF
SUBSTANCE
Elements are substances that contain only one type of atom and are
chemically the simplest substance.
An atom is the smallest part of an element that has the properties of
that element.
A molecule is a particle made of two or more atoms bonded
together.
- Molecule of an element contains the same element (Ex- Br2 )
- Molecule of a compound contains two or more elements (Ex- HBr)
o A compound is a substance containing atoms of different elements
combined together.
o An ion is a species that has gained electrons to form negative
charges (anion) or lost electrons to form positive charges (cations).
o Elements with:
- Single atom ; monoatomic
- Two atoms ; diatomic
- Several atoms ; polyatomic
In order to write a chemical equation:
- Convert the names of elements/compounds into their formulas
and write in the form of reactants to products
- Balance the equation
- Include the state symbols ( solids/precipitates; s. Solutions; aq.
Gases; g. Pure liquids; l. )
Ionic equations shows only the atoms/molecules that are involved
and not the spectator ions (an ion that appears unchanged at the
end of the reaction).
Acids you need to know:
o Hydrochloric acid – HCl
o Nitric acid – HNO3
o Sulphuric acid – H2 SO4
o Phosphoric acid – H3 PO4
, Reactions of acids
1) Metal + acid = salt of hydrogen
Observations: bubbles of hydrogen gas. If the salt formed is soluble, a
solution will form.
2) Metal oxide + acid = salt + water
Observations : a solution forms.
3) Acid + alkali = salt + water
Observations: temperature rises.
4) Metal carbonate + acid = salt + water + carbon dioxide
Observations : bubbles of carbon dioxide forms.
Displacement reactions are reactions in which are more reactive
element replaces a less reactive element.
Displacement reactions can happen involving halogens ( reactivity
of halogens decreases down the group)
Displacement reactions can happen involving metals (according to
reactivity series)
A reaction in which an insoluble solid is formed when two solutions
are mixed is called a precipitation reaction. These are useful in
certain chemical tests.
INTRODUCTION TO ORGANIC CHEMISTRY
TOPIC 1 – FORMULAE, EQUATIONS AND AMOUNT OF
SUBSTANCE
Elements are substances that contain only one type of atom and are
chemically the simplest substance.
An atom is the smallest part of an element that has the properties of
that element.
A molecule is a particle made of two or more atoms bonded
together.
- Molecule of an element contains the same element (Ex- Br2 )
- Molecule of a compound contains two or more elements (Ex- HBr)
o A compound is a substance containing atoms of different elements
combined together.
o An ion is a species that has gained electrons to form negative
charges (anion) or lost electrons to form positive charges (cations).
o Elements with:
- Single atom ; monoatomic
- Two atoms ; diatomic
- Several atoms ; polyatomic
In order to write a chemical equation:
- Convert the names of elements/compounds into their formulas
and write in the form of reactants to products
- Balance the equation
- Include the state symbols ( solids/precipitates; s. Solutions; aq.
Gases; g. Pure liquids; l. )
Ionic equations shows only the atoms/molecules that are involved
and not the spectator ions (an ion that appears unchanged at the
end of the reaction).
Acids you need to know:
o Hydrochloric acid – HCl
o Nitric acid – HNO3
o Sulphuric acid – H2 SO4
o Phosphoric acid – H3 PO4
, Reactions of acids
1) Metal + acid = salt of hydrogen
Observations: bubbles of hydrogen gas. If the salt formed is soluble, a
solution will form.
2) Metal oxide + acid = salt + water
Observations : a solution forms.
3) Acid + alkali = salt + water
Observations: temperature rises.
4) Metal carbonate + acid = salt + water + carbon dioxide
Observations : bubbles of carbon dioxide forms.
Displacement reactions are reactions in which are more reactive
element replaces a less reactive element.
Displacement reactions can happen involving halogens ( reactivity
of halogens decreases down the group)
Displacement reactions can happen involving metals (according to
reactivity series)
A reaction in which an insoluble solid is formed when two solutions
are mixed is called a precipitation reaction. These are useful in
certain chemical tests.
