http://mrged.flexinet.com.au. Types of Chemical Change. You already know about,. 1.The two main types of chemical bonding. 2. Writing chemical formulas (formulae). This week we will find out about;. 1.Synthesis Reactions. 2. Decomposition reactions. 3. Single replacement reactions.
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Types of Chemical Change
You already know about,
1.The two main
types of chemical bonding
2. Writing chemical formulas
This week we will find out about;
2. Decomposition reactions
3. Single replacement reactions
4. Double replacement reactions
The Periodic Table
Types of chemical bonding. Revision
This type of bonding
will occur when a metal reacts with a non -metal
It always involves a complete transfer of electrons
1 Na reacts with 1 Cl
Formula = NaCl
View animation at
This type of bonding
will occur when a non- metal reacts with a non -metal
Here both atoms will share electrons
In this section we will find out how to write chemical FORMULAE
Rules leading to correct formula
1. Positive ions (cations) can join to negative ions (anions)
2. Positive ions usually form the first part of the name (99% cases)
3. If the formula is correct there is no overall charge
Please copy into your exercise books
4. If you have more than one polyatomic ion it is placed inside brackets
Essential training ions
Chemical Formulae 1.
Chemical Formulae 2.
Chemical Formulae 3.
Chemical Formulae 4.
Chemical Formulae 5.
Chemical Formulae 6.
Chemical Formulae 7.
Chemical Formulae 8.
1. lithium sulphite
2. barium hydroxide
3. copper carbonate
4. hydrogen sulphide
5. magnesium nitride
6. ammonium bromide
7. aluminium oxide.
In chemistry there are millions of chemical reactions.
But most reactions can be classified as
one of four types of reactions:
Synthesis: A + B -> AB
Decomposition: AB -> A + B
Single Replacement: A + BC -> AC + B
Double Replacement: AB + CD -> AD + CB
In a synthesis reaction
(also known as a composition reaction),
two substances combine to form a larger substance.
Here are 3 synthesis reactions:
Hydrogen + oxygen yields water
2H2 + O2 -> 2H2O
Magnesium + nitrogen yields magnesium nitride
3Mg + N2 -> Mg3N2
Iron + sulphur yields iron(II) sulphide
Fe + S -> FeS
In a decomposition reaction, a larger substance
breaks apart and forms two or more simpler substances.
The first thing you may notice about a decomposition reaction
is that it is the complete opposite of a synthesis reaction.
In fact many synthesis reactions
can be reversed into a decomposition reaction.
When you burn hydrogen gas,
the hydrogen combines with oxygen to produce water.
2H2 + O2 -> 2H2O
With an electrical current, water can be
decomposed into hydrogen and oxygen gas.
2H2O -> 2H2 + O2
Some examples of decomposition
Heat copper carbonate and it will decompose
(Refer to flash animation .swf)
CuCO3 -> CuO + CO2
(Most carbonates decompose producing the oxide and carbon dioxide)
Heat lead(11) hydroxide and it will decompose
Pb(OH)2 -> PbO + H2O
6x Quicktime mov files
1. Watch all 12 mov files (available on SET drive)
2. Classify each as either, synthesis, decompostion, single of double replacement reactions
3. Write a correct chemical equation for each!
Some may require some research
In a single replacement reaction,
a more active element replaces
a less active element in a compound.
Here Mg is more reactive than Pb
If fluorine gas is bubbled through a solution of
potassium chloride, the fluorine will replace the chlorine.
This reaction can be represented as follows;
2KCl + F --> 2KF + Cl
No surprise! fluorine is more reactive than chlorine
Please note this PPT may be updated over the weekend