Unit F: Chemical Reactions
Unit 6: Chemical Reactions
What is a Chemical Reactions?
Rxn Bkt p.2
Balancing Chemical Equations
1) Cannot change a subscript for a chemical formula
2) Can add a coefficient in front of a chemical formula
3) Coefficient multiplies the formulas’ number of atoms
2 Ca3(PO4)2: 6 Ca, 4 P, 16 O
4) Same number of atoms of each element on the reactants’
and products’ sides
Examples Hebden p.107-110
Exercises Heb p.110-112: even numbers, Rxn Bkt p.6#1
Converting Word Equation into Chemical Equation:
1) Use periodic table
Symbol and metal or non metal
2) Use naming concept map
Ionic, covalent or elemental
Ionic: metal + non metal ions
Use list of polyatomic ions (back of periodic table)
Covalent: non metal + non metal
3) Elemental: pure element Ex: Pb, Ni, Au
4) Hof Brincl: diatomic molecules (H2, O2, F2, Br2, I2, N2, Cl2)
5a) With an acid use:
When I ate it, it’s icky (sulphate---sulphuric acid)
When I bite it, it’s delicious( sulphite----sulphurous acid)
b) Acid with an element
Hydro + element + ic
Hydrochloric acid : HCl
6) Trivial names: (Common old names)
Ammonia: NH3
Acetic acid: CH3COOH
States and Symbols of Chemical Reactions
+: combining
( yielding or making
s, l, g, aq: solid, liquid, gas, aqueous (dissolved in water)
reactants ( products
Exercises: Heb p.113#57-64: odd numbers
6 Types of Chemical Reactions (Hebden p.114-118)
1) Synthesis (Velcro couple)
A + B ( AB
metal non metal metal ion/non metal ion
Ex: rusting a nail (as a product, iron is +3)
Fe(s) + O2(g) ( Fe2O3(s)
Nail iron (III) oxide
Balanced:
4Fe(s) + 3O2(g) ( 2Fe2O3(s)
2) Decomposition (Break up)
AB ( A + B
Ex: Decomposition of hydrogen peroxide (using a catalyst)
H2O2(l) ( H2O(g) + O2(g) (Remember Hof Brincl)
Balanced:
2H2O2(l) ( 2H2O(g) + O2(g)
3) Single Replacement (New kid in the block)
a) AB + C ( CB + A
metal metal metal metal
non metal non metal
Ex: Adding steel wool to copper(II) sulphate solution
Fe(s) + CuSO4 (aq) ( FeSO4 (aq) + Cu(s)
b) AB + C ( AC + B
metal non metal metal non metal
non metal non metal
Ex: CaF2 + Cl2 ( CaCl2 + F2
Activity Series: How do we use it? Rxn Bkt p.3
4) Double Replacement Cross over charges (switching partners)
AB + CD ( AD + CB
K2SO4 (aq) + AgNO3(aq) ( Ag2SO4(s) + KNO3(aq)
metal metal
non metal non metal
Using an ion box
K2SO4 (aq) + 2AgNO3(aq) ( Ag2SO4(s) + 2KNO3(aq)(Balanced)
5) Neutralization (special type of double replacement)
acid + base ( salt + water
ionic compound
H2SO4 + 2 NaOH ( Na2SO4 + 2 H2O
Sulphuric acid
6) Combustion of Hydrocarbons
hydrocarbon: contains hydrogen and carbon atoms
Reacting with oxygen gas
2 C8H18 + 25 O2 ( 16 CO2 + 18 H2O
octane
Exercises: Heb p.118#65-66
**T**Predicting the Products of a Reaction:
1) General Rules:
1) Find the chemical formulas for each reactant using:
i) Periodic table
ii) Naming concept map
iii) List of polyatomic ions (P.A.I)
2) Looking at the reactants, select the reaction type:
Synthesis, decomposition, combustion (O2), SR, DR, Neutralization
3) Find the relevant products and beware of:
(i) Hof Brincl
.Diatomic molecule by themselves (in pair)
.H2, O2, F2, Br2, I2, N2, Cl2
(ii) A metal is always mono-atomic (one atom) and uncharged
(iii) Ionic product: metal ion(cation) + non metal ion(anion)
2) Single Replacement Products:
i) Locate the substance that is replacing the ion in the compound
Metal ( cation+ (metal ion)
Non metal ( anion- (non metal ion)
ii) Locate both substance and ion in the Activity Series (Rxn Bkt p.3)
Substance on top can replace the other substance on the bottom
Ex 1: Magnesium bromide + chlorine ( ?
MgBr2 + Cl2 ( ?
Br2 < Cl2 Activity Series: Refer to Rxn Bkt p.3
Answer: MgBr2 + Cl2 ( MgCl2 + Br2
Ex 2: Rnx Bkt p.12#2
Aluminum + iron (III) oxide ( ?
Al + Fe2O3 ( ?
Al > Fe Activity Series: Refer to Rxn Bkt p.3
Balanced Equation:
2Al + Fe2O3 ( 2Fe + Al2O3
3) Double Replacement Products:
i) Set up an ion box containing cations and anions
ii) Insert cations and anions in the ion box
iii) Find the products by switching cations with anions
Ion Box
|Cation |Anion |Product |
| | | |
| | | |
Ex-1: silver nitrate + zinc chloride( ?
AgNO3 + ZnCl2 ( 2 ionic substances reacting (DR)
Ion box
|Cation |Anion |Product |
| | |(Criss cross) |
|Ag+ |NO3- |AgCl |
|Zn2+ |Cl- |Zn(NO3)2 |
2AgNO3 + ZnCl2 ( 2AgCl + Zn(NO3)2
Ex-2: Sulfuric acid + sodium hydroxide ( ?
H2SO4 + NaOH ( ?
Ion box
|Cation |Anion |Product |
| | |(Criss cross) |
|H+ |SO42- | H2O |
|Na+ |OH- | Na2SO4 |
H2SO4 + 2NaOH ( 2H2O + Na2SO4 (DR also neutralization rxn)
3) Hydrocarbon Combustion
Hydrocarbon: contains hydrogen and carbon (ex: C3H8)
Combustion: O2 as a reactant (oxygen molecule(Hof Brincl)
Products: carbon dioxide (CO2) and water (H2O)
Ex: butane combustion in a lighter
C4H10 + 13 O2 ( 4CO2 + 5H2O 1, 6.5, 4, 5
2 8 + 5 = 13 oxygen atoms
After multiplying the whole equation by two:
2C4H10 + 13 O2 ( 8CO2 + 10H2O 2, 13, 8, 10
Exercises: Heb p.118#67, Rxn Bkt p.6-8#2
Thermochemical Reactions
Def:Energy Changes in Chemical Reactions (Endo/Exo Chart Rxn Bkt p.4)
2 types of energy changes:
Exothermic(hot) or endothermic(cold)
Exo Rxn: Carbon Tree Reaction
(i) 2 C12H22O11(s) + 2 H2SO4(aq) + O2(g) (
22 C(s) + 2 CO2(g) + 24 H2O(g) + 2 SO2(g) + 400 kJ
Energy term is found as a product
(ii) 2 C12H22O11(s) + 2 H2SO4(aq) +O2(g)(
22 C(s) + 2 CO2(g) + 24 H2O(g) + 2 SO2(g) (H = -400 kJ
Endo Rxn: Smelling Salts
(i) 2 NH4SCN(s) + Ba(OH)2•8H2O(s) + 500kJ (
2 NH3(g) + 10 H2O(l) + Ba(SCN)2(aq)
Energy term is found as a reactant
(ii) 2 NH4SCN(s) + Ba(OH)2•8H2O(s) (
2 NH3(g) + 10 H2O(l) + Ba(SCN)2(aq) (H = 500kJ
Lab: Thermochemical Reactions
Exercises: Heb p.121#70-75, p.122#76-80, Rxn Bkt p.5, p.8#3
................
................
In order to avoid copyright disputes, this page is only a partial summary.
To fulfill the demand for quickly locating and searching documents.
It is intelligent file search solution for home and business.
Related searches
- what are the chemical reactions for photosynthesis
- chemical reactions with baking soda
- chemical reactions calculator
- chemical reactions cellular respiration
- chemical reactions within the body
- chemical reactions worksheet
- chemical reactions in cellular respiration
- cycle of chemical reactions cell respiration
- chemical reactions in chemistry
- types of chemical reactions key
- types of chemical reactions lab key
- chemical reactions experiments high school