Term
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Definition
Most singular ions, Na+...
Only NH4+ applicable |
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Term
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Definition
Most molecular/compound ions, NO3-...
Cl-, Br-,I-, O2- |
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Term
Soluble Anions
NO3-, Cl-, Br-, I-, SO4-2
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Definition
Insoluble with
Ag+ Pb+2 ... |
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Term
Insoluble Anions
OH- S-2 CO3-2 PO4-3
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Definition
Soluble with
Na+ K+ NH4+(except OH-) Ba+(only OH-)
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Term
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Definition
Average mass of one atom of the element as compared to 1/12 mass of one atom of C-12 |
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Term
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Definition
1 ppm = 1 mg/dm3
= 1 x 10-3 g of substance
1 dm3 of solution |
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Term
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Definition
actual
theoretical
x 100% |
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Term
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Definition
1. XXX reactants not pure
2. Loss of XXX products during transfer
3. XXX side reaction occurs
4. XXX reaction does not reach completion. |
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Term
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Definition
Molecular Mass of Desired Product
Sum of Molecular Mass of all reactants/products
x 100 |
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Term
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Definition
1. Enthalpy of Products < Enthalp of Reactants
2. -ve Enthalpy Change
3. High Temperature
4. Heat lost to surroundings
5. Bonds formed
[image]
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Term
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Definition
1. Enthalpy of Products > Reactants
2. +ve Enthalpy Change
3. Lower Temperature
4. Gain from surroundings
5. Bonds broken
[image] |
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Term
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Definition
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Term
Standard Enthalpy of Formation |
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Definition
Keywords
1 mole of compound
From its elements
Standard states at 298K and 1 atm
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Term
Standard Enthalpy of Combustion |
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Definition
1 mole of substance
Burns completely in oxygen
at 298K and 1 atm |
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Term
Standard Enthalpy Change of Neutralisation |
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Definition
1 mole of water is formed
From neutralisation of 1 acid by 1 alkali
at 298K and 1 atm |
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Term
Standard Enthalpy Change of Atomisation |
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Definition
1 mole of separate gaseous atoms
From element in its standard state
at 298K and 1 atm |
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Term
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Definition
Break 1 mole of covalent bond
in gaseous molecules |
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Term
Experimental method to find Enthalpy Change
Calorimeter |
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Definition
- M x C x ΔT
- Only use mass of solution and solution's C as substance/powder etc. have negligible C and M |
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Term
Possible errors in using calorimeter to measure Enthalpy Change of Neutralisation |
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Definition
1. Heat lost to calorimeter.
2. Assumption density and specific heat capacitry of solution same as water. |
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Term
Calorimeter - Why Polystyrene cup and not beaker? |
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Definition
1. Reduces heat lost.
2. Inert/ Does not react with most chemicals.
3. Does not absorb much heat.
4. If use beaker, ΔH will decrease. |
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Term
Enthalpy Change of Combustion of fuel |
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Definition
Black solid - Carbon, formed due to incomplete combustion
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Term
Experimental of Combustion < Theoretical
1. Heat lost to surroundings
2. Some heat goes to beaker instead
3. Incomplete combustion due to inadequate O2
4.Condition of products not standard (water vapour, endothermic reaction) |
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Definition
Resolutions
1. Use shields
2. Use copper tin
3. No shields |
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Term
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Definition
To ensure all XXX have completely reacted
OR
To ensure all XXX have neutralised completely (if neutralisation) |
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Term
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Definition
If using enthalpies of formation,
1. Arrows go up
2. Elements as middle part
If using enthalpies of combustion,
1. Arrows go down
2. Combustion products as middle part |
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Term
Why XXX reaction cannot be determined directly but calculated through Hess's Law?
(Alkene to alkane)
CnH2n + H2 -> CnH2n+2 |
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Definition
1. Reaction cannot be conducted in lab due to H2 being flammable
2. Ethane etc. may undergo combustion
3. Reaction rate is too slow. |
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Term
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Definition
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Term
3 uses of Table of average standard bond enthalpies |
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Definition
1. Compare strength of bonds
2. Understand struscture and bonding
3. Calculate ΔHf and ΔHreaction using Hess's Law |
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Term
Ensuring accuracy of experiments |
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Definition
1. Constant stirring of water to ensure even temperature
2. Use screen/coppertin/polystyrene board/lid etc to prevent heat loss
3. Use more accurate apparatus (thermometers that read up to 0.1, use pipetter not measuring cylinder...)
4. Take temperature every 30s... |
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Term
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Definition
Uncertainty of Error
Value of measurement
x 100 |
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Term
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Definition
Reliability : repeat experiment and get average value
Accuracy :
1. Use precise instruments
2. Use larger volume/mass... |
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Term
Which sub-atomic particle would deviate the most? |
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Definition
Electron as it has a lower mass than proton. |
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Term
Isotopes
1.Same Chemical properties
2.Different Physical properties
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Definition
1. same amount of electrons/electronic configuration
2. Masses are different |
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Term
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Definition
1. Vaporisation (gaseous atoms to move through instrument)
2. Ionisation (bombarded by high energy electrons and 1 electron is knocked out of atom)
3. Acceleration (Electric field)
4. Deflection (Magnetic field according to m/z ratio)
5. Detection (shows how many ions of each m/z ratio in sample) |
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Term
Usage of mass spectrometry |
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Definition
1. Archeology - Radiocarbon dating using C-14
2. Geographical - Detect oil composition
... |
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Term
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Definition
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Term
Atomic Radii
1.Decrease across Period
2.Increase down Group
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Definition
1. More protons but electrons in same energy level/shells, force of attraction increase
2. More protons but electron in higher energy levels, outermost electrons more shielded, force of attraction decreases |
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Term
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Definition
Remove 1 mole of electrons
From 1 mole of gaseous atoms
to form 1 mole of gaseous positive ions |
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Term
Factors of Ionisation energy |
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Definition
1. Distance from nucleus (atomic radii)
2. Nuclear charge (number of protons)
3. Shielding effect (by inner shell electrons) |
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Term
Trends in first ionisation energy
1. Increase across period
2. Decrease down the group |
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Definition
1. Atomic radius smaller, Nuclear charge increases, Negligible shielding as all in same shell, FOA ↑
2. Atomic radius increase but cancelled off by increase in number of protons, but shielding effect increase, FOA decrease |
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Term
First ionisation energies do not increase smoothly across period |
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Definition
Due to presence of subshells |
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Term
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Definition
1 mole of electrons
Added to 1 mole of atoms
In gaseous state |
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Term
First EA
1. Increase across period
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Definition
1. Nuclear charge increase, atomic radius smaller,negligible shielding |
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Term
Why first EA always exothermic and why second EA endothermic? |
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Definition
1. To form an attraction between incoming electrons and nucleus
2. Repulsion between incoming electron and negative ion |
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Term
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Definition
Electrostatic force of attraction between oppositely charged ions |
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Term
Giant Ionic Lattic Structure |
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Definition
1. Neatly arranged
2. Very high melting & boiling pt. - large amount of energy to overcome strong electrostatic attractions and separate ions
3. Hard but brittle - Any dislocation=layers moving=repulsion occurs=splits crystal
4. Good electrical conductivity in molten or aqueous state only - solid=ions held strongly by lattice, liquid/molten=mobile ions & conduction takes place
5. Very high density - higher than water but lower than typical metals |
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Term
3D arrangement of ions in NaCl |
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Definition
6 Na+ ion around each Cl- ion
OR
Cubic structure with alternate Na+ and Cl- ions |
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Term
Size of cation
1. < size of atom
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Definition
1. Number of electron shell decreases, higher p/e ratio, Effective nuclear charge increases, remaining e- are pulled in closer to nucleus |
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Term
Size of Anion
1. > Size of Atom
2. Increases down the group |
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Definition
1. Same number of electron shell but p/e ratio decreases, Effective nuclear charge decreases, expansion of electron cloud
2. Number of protons increases, but electrons in higher/outer shell, more shielding, FOA decreases |
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Term
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Definition
Ions with same number of electrons
H- Li+ Be2+ B3+ - 2 electrons in each ion |
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Term
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Definition
1 mole of ionic compound
formed from gaseous ions under standard conditions |
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Term
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Definition
1. larger ionic charge = larger lattice energy
2. smaller sum of ionic radii=larger lattice energy |
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Term
Determination of Lattice energy |
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Definition
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Term
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Definition
higher when amount of energy released high |
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Term
Polarisation in ionic bonds |
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Definition
Cations - larger charge= higher polarising power
- smaller redius = higher polarising power
Anions - larger radius= higher polarisability |
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Term
Why CaI2 more covalent than KI? (Why more difference between theoretical and experimental lattice energy?) |
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Definition
-higher charge, smaller radius
-more polarising
-able to distort electron cloud to a greater extent |
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Term
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Definition
Electrostatic force of attraction between the nuclei and shared pair of electrons |
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Term
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Definition
Shared pair of electrons which has been provided by one of the bonding atoms |
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Term
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Definition
A giant lattice of positive metal ions fixed in position and surrounded by a sea of electrons |
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Term
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Definition
Force of attraction between the positive metal ion and negative delocalised electrons |
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Term
Factors on strength of metallic bond |
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Definition
1. Ionic radius
2. Ionic charge
3. Valence electrons (number of delocalised electrons) |
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Term
Physical properties of Giant Metallic Lattices
1. V.high melting and boiling pt.
2. Good malleability and ductility
3. Good electrical conductivity in both solid and molten states
4. V.high density |
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Definition
1. Strong electrostatic attractions between cations and delocalised electrons
2. Ions and delocalised electrons move around each other, will not break as cations still surrounded by electrons
3. Delocalised electrons free to move and can conduct electricity when a potential difference is applied
4. Higher than water and ionic compound |
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Term
Why strength of bond between simple molecules/simple atoms weak? |
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Definition
weak Van der Waals forces between molecules/atoms |
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Term
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Definition
1. Structural - same molecular formula but different structure
2. Geometrical -restricted rotation of Carbon-Carbond double bond(C=C)
- Both C atoms of C=C must have 2 different groups/atoms
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Term
Cis/trans isomers
- must have at least 1 same group of atoms each side |
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Definition
Cis - same group of atoms at same side of C=C
Trans - Groups at different sides
Limits - When all different groups, don't work |
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Term
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Definition
Use mass instead (group with higher mass is used)
E- Different
Z - Same |
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Term
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Definition
1. CnH2n+2
2. Only single bonds
3. 4 H bonds to every C atom
4. Saturated Hydrocarbon |
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Term
Fractional distillation (of crude oil) |
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Definition
1. Higher = not so pure, lower boiling/melting point
2. Middle area purest
3. Lowest= bitumen, Highest=Gas,
Gas<Petrol<Chemicals<Aircraft fuel<Central Heating fuel<Lube<Power Station/Ship fuel<Candles and grease<Road |
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Term
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Definition
Use of high temperature or catalyst to break large hydrocarbon to smaller molecules of alkane/alkene
C-C bonds broken
(Can also occur when no oxygen present)
E.g of catalyst zeolite Al2O3 |
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Term
Why short chains high in demand? |
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Definition
1. Small chain of alkane allow for use as fuel
2. Small chain of alkene for use in polymer production |
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Term
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Definition
Process in which straight-chain alkanes form rings or branched chains in presence of high temperature or catalyst(E.g. Pt) |
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Term
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Definition
1. Combustion of alkanes
2. Free radical substitution (E.g with Cl2) (must have UV) |
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Term
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Definition
1. Homolytic
2. Heterolytic |
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Term
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Definition
1. CnH2n
2. C=C
3. Unsaturated hydrocarbon
4. More reactive than alkane
5. Can form cis-trans (E/Z) isomers |
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Term
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Definition
Consists of 1 σ (sigma) and 1 ∏ (pi) bonds |
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Term
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Definition
1. Overlap of 2 s-orbitals
2. Overlap of 2 p-orbitals (one end to another end)
3. Overlap of one s-orbital and p-orbital |
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Term
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Definition
Side-on overlap of 2 p-orbitals (at 2 points) |
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Term
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Definition
Sigma bond overlaps are closer to nuclei |
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Term
C=C - region of high electron density |
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Definition
Electrons more diffused and less firmly held. So easily attacked by electrophiles. |
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Term
Chemical reactions of alkene |
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Definition
1. Combustion
2. Electrophilic addition
3. Oxidation
4. Polymerisation |
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Term
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Definition
Type of reaction in which an electrophile is attracted to the electron density in the C=C and added across the double bond to form one product. |
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Term
Markovnikov's rule
(My understanding of it) |
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Definition
The more hydrogen atoms attached to the carbon atoms of the double bond(reactant) in the product, the more likely it is to be the major product. (more stable) |
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Term
Test for C=C bond (double bond) |
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Definition
Add few drops of Bromine water, Br2 to alkene.
It will be decolourised from brown to colourless. |
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Term
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Definition
Process in which many small molecules (monomers) join together into large molecules (polymers) consisting of repeating units |
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Term
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Definition
alkene monomers are joined together without elimination of any atoms/molecules |
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Term
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Definition
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Term
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Definition
1. Polyethene - food wrap
2. Polypropene - yogurt tubs
3. Polybutene - Rubber piping
4. Polychloroethen (PVC) - Cable insulation
-Make flexible using plasticizer to allow chains to slide
5. Polytetrafluoroethene (Teflon) - Non-stick coating on frying pan
6. Polyphenylethen (Polystyrene) - Foam packaging, polystyrene cup |
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Term
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Definition
1. Use non-renewable resources (from crude oil)
2. High-energy production costs
3. Non-biodegradable - landfill problem
4. Does not burn easily (requires extremely high heat) |
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Term
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Definition
1. Reducing
2. Recycling
3. Burn waste (Produces energy)
4. Feedstock (Convert waste to hydrocarbon)
5. Biodegradable polymers (made from natural polymers - starch, cellulose) |
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Term
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Definition
Reducing energy consumption of polymer manufacture |
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