(2.3) types of chemical reactions (p144-147). word equation a word equation - states what reacts and...
TRANSCRIPT
Word Equation
A word equation - states what reacts and what is
produced- uses words instead of formulas to
describe a chemical reaction
Chemical Reaction
Reactants- the starting materials in a reaction.
Products- the new materials formed in a reaction.
Chemical Equation
Describes a chemical reaction
reactants products
Note: The symbol () can be read as yields or forms or produces
Word Equation-Examples
Ex 1: magnesium + oxygen magnesium
oxide what reacts what is
produced (reactants) (products)
Word Equation-Examples
Ex 2:zinc + hydrochloric acid hydrogen + zinc
chloride
what reacts what is produced (reactants) (products)
Demo Time!
1)Magnesium reacts with oxygen2)Copper sulfate decomposes3)Zinc reacts with hydrochloric acid4)Lead nitrate reacts with potassium
iodide5)Ethanol burns
CLASSWORK Worksheet 2.3 (A)-complete and hand in
REMINDERS:Did you complete and hand in ?
- Workbook p 46-52- Worksheet “Periodic Table” Q # 1-11
Chemical Reactions – 4 Types
4 main types of chemical reactions Synthesis Decomposition Single displacement Double displacement
Intro animation (see p145)
1. Synthesis Reactions
Two or more reactants combine to form a new product.
GENERAL CHEMICAL EQUATION (GCE)
2. Decomposition Reactions
A compound is broken down into elements or smaller compounds.
GENERAL CHEMICAL EQUATION (GCE)
Is each reaction synthesis or decomposition?
1. Ag2CO3 Ag2O + CO2
2. P4 + O2 P4O10
3. Fe + O2 Fe2O3
4. KClO3 KCl + O2
Decomposition
Synthesis
Decomposition
Synthesis
3. Single Displacement Reactions
One element replaces another element to form a new compound.
GENERAL CHEMICAL EQUATION (GCE)
Or
Single Displacement- Examples calcium + hydrogen bromide
calcium bromide + hydrogen
Br2 + 2 KI + 2 KBr + I2
4. Double Displacement Reactions
In a double displacement reaction the metal ions in two compounds switch places…”partner swap”
GENERAL CHEMICAL EQUATION (GCE)
Double Displacement- Examples
barium sulfide + potassium iodide barium iodide + potassium sulfide
AgNO3 + KCl AgCl + KNO3
Is it single displacement (SD) or double displacement (DD)?
1. NaBr + Ca(OH)2 CaBr2 + NaOH
2. Pb + H3PO4 H2 + Pb3(PO4)2
3. Li3N + NH4NO3 LiNO3 + (NH4)3N
4. CuSO4 + Al Al2(SO4)3 + Cu
DD
SD
SD
DD
Putting it all together: Which Type of Reactions are the following:
a) H2O H2 + O2
b) SiO2 + HF SiF4 + H2O
c) H2 + O2 H2O
d) Cu + HCl H2 + CuCl2Single
Displacement
DoubleDisplacement
Synthesis
Decomposition
Predict What Gets Made
1. Al + Cl2
2. CuF2 + K
3. MgO
4. CaS + FeN
Pick your answer from this box
Mg Ca3N2 F2 KF2
Cu N2 AlCl2 CaFe
AlF3 FeS O2 SN
Chemical Reactions – 5th Type
Another reaction type is Combustion (also called burning)
The burning of fossil fuels always needs oxygen and will yield predictable products.
Complete combustion: lots of O2
Fuel + oxygen carbon dioxide + water(in general) CxHy + O2 CO2 + H2O CH4 + 2 O2 CO2 + 2 H2O
5. Combustion Reactions
The burning of fossil fuels always requires oxygen and will yield predictable products.
Complete combustion: lots of O2
Fuel + oxygen carbon dioxide + water
CxHy + O2 CO2 + H2OCH4 + 2 O2 CO2 + 2 H2O
Combustion Continued
Incomplete combustion: occurs when there is not enough O2
The products are different than with complete combustion.
CxHy + O2 C + CO + CO2 + H2O
Recall: Chemical Reactions – 5 Types
Types of chemical reactions: Synthesis Decomposition Single displacement Double displacement Combustion
Chemical Formulas The chemical formulas of most elements
are written simply as the symbol in the periodic table
Ex: magnesium, Mg sodium, Na
But there are some elements that contain more than one atom.
For a list, see Table 2.9 p147 or your workbook p55
Chemical Equation
From the word equation you can now write a chemical equation:
Ex:a) sodium chloride sodium +
chlorine NaCl Na + Cl2b) hydrogen + oxygen water H2 + O2 H2O