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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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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 4. Double replacement reactions
Ionic Bonding This type of bonding will occur when a metal reacts with a non -metal It always involves a complete transfer of electrons • It always produces IONS (charged particles)
1 Na reacts with 1 Cl Formula = NaCl View animation at http://mrged.flexinet.com.au
Covalent Bonding This type of bonding will occur when a non- metal reacts with a non -metal Here both atoms will share electrons • It always produces molecules (particles with no charge)
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
Positive ions (Cations) Negative ions (Anions) + 1 - 1 fluoride F sodium Na chloride Cl potassium K bromide Br hydroxide OH hydrogen H Essential training ions nitrate NO3 lithium Li silver Ag hydrogencarbonate HCO3 ammonium NH4 - 2 carbonate CO3 magnesium Mg +2 oxide O calcium Ca sulphide S barium Ba zinc Zn sulphate SO4 iron(11) Fe sulphite SO3 copper Cu chromate CrO4 +3 - 3 nitride N aluminium Al chromium Cr phosphate PO4 iron(111) Fe
sodium fluoride Chemical Formulae 1. IONS CHARGES NUMBERS Na F FORMULA
magnesium fluoride Chemical Formulae 2. CHARGES IONS NUMBERS Mg F FORMULA
Chemical Formulae 3. silver hydroxide CHARGES IONS NUMBERS Ag OH FORMULA
calcium nitrate Chemical Formulae 4. CHARGES IONS NUMBERS Ca NO3 FORMULA
ammonium carbonate Chemical Formulae 5. CHARGES IONS NUMBERS NH4 CO3 FORMULA
aluminium bromide Chemical Formulae 6. CHARGES IONS NUMBERS Al Br FORMULA
chromium sulphide Chemical Formulae 7. CHARGES IONS NUMBERS Cr S FORMULA
Chemical Formulae 8. BLANK ITEM CHARGES IONS NUMBERS FORMULA
Try these: 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
Synthesis (Composition) C O O O O C 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
Decomposition 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
PrecipitaReact.MOV FormWater.MOV FORMALUMBRO.MOV THERMITE.MOV NitrogTriiodide.MOV REDUCTIONCUO.MOV 6x Quicktime mov files
TRY THESE: 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
Single Replacement In a single replacement reaction, a more active element replaces a less active element in a compound. more reactive less reactive
Single Replacement Here Mg is more reactive than Pb
Single Replacement 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