UNIT 10 CARBON CHEMISTRY QUÍMICA 1 BATXILLERAT. Isomerism Two chemical compounds are isomers when...
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Transcript of UNIT 10 CARBON CHEMISTRY QUÍMICA 1 BATXILLERAT. Isomerism Two chemical compounds are isomers when...
UNIT 10
CARBON CHEMISTRY
QUÍMICA 1 BATXILLERAT
Isomerism
Two chemical compounds are isomers when they have the same simplified molecular
formula but different developed molecular formulae.
Example:
Planar or structural isomerism (I)
Example:
Planar chain isomerism occurs in
compounds that have the same formula but
that show different ways of arranging
themselves, that is, different chains.
Example:
Planar functional isomerism occurs
in compounds that have the same
formula but different functional
groups.
Planar functional isomerism occurs in compounds that have the same formula
but different functional groups.
Example:
Planar or structural isomerism (II)
Planar positional isomerism occurs in compounds that
have the same formula but that differ in the position of an
atom or a group of atoms, the position of double or triple
bonds or the position of a functional group.
Examples: Position of an atom or group of atoms:
Position of double or triple bonds: Position of a functional group
Spatial isomerism or stereoisomerism (I)
Geometrical spatial isomerism occurs generally in
compounds with a double bond or in cyclic structures in which
the arrangement of atoms, or groups of atoms, around the
same centre is different from one to another.
Examples:cis-2-butene
trans-2-butene
Spatial isomerism or stereoisomerism (II)
Optical spatial isomerism occurs in compounds whose atoms are connected in the
same relative position with respect to a carbon atom, but with a different spatial
arrangement, so that one is the mirror image of the other.
The two compounds are called enantiomers.
Examples:
Polymers
Types of reaction
Condensation polymerisation:
Addition polymerisation:
Macromolecules are formed by the combination of lots of other simple molecules. If these simple molecules are identical structural units that repeat, the macromolecules
are called polymers, and each of the structural units that makes up the polymer is called
a monomer. Polymerisation is the chemical reaction to produce a polymer from a monomer.
Classification of polymers
According to the type of monomer
Homopolymers.
Copolymers.
According to the structure of the polymer
Linear polymers.
Branched polymers.
Natural polymers
Natural
polymers
Cellulose
Proteins
Nucleic acids
Cotton. Linen. Rayon.
Globular polymers. Fibroses.
Deoxyribonucleic acid (DNA). Ribonucleic acid (RNA).
Molecule of cellulose
Molecule of DNA
Synthetic polymers
Resins: condensation polymers in which the monomer has two or more functional
groups (bakelite). Elastomers or synthetic rubbers: addition polymers in which the monomer is a
molecule with double bonds.
Fibres: condensation polymers. Polyamides. Polyesters.
amide bond
Motor fuels: internal combustion
Origin of fuels
Fossil or mineral, from crude oil or
natural gas: petrol, diesel, kerosene,
butane, etc. Derived from modified plant products:
biofuels.
Characteristics of fuels for Otto and diesel motors
Octane number. Heating value. Physical state. Viscosity. Evaluation of pollution: ecological
effects depending on the origin.
Types of combustion engine
Alternating. Alternating internal reaction:
Ignition by spark or Otto motor. Ignition by compression or diesel
motor.
Fuels
Environmental problems caused by the use of coal, oil and natural gas
They are a non-renewable source of
energy and are running out. They generate a large number of
atmospheric contaminants They degrade the areas where oil spillages
occur. They produce carbon dioxide, which is the
main cause of the greenhouse effect.
Biofuels
Biofuels are fuels produced from biomass and, in general, are considered to be
renewable energy.
Types of biofuel Solid: wood, crop residues, animal waste, etc. Liquid: bioalcohol or biodiesel. Gaseous: biogas.
Advantages of the use of biofuels
Biomass is abundant in many regions
of the Earth. It is a renewable resource that does not
produce net emissions of carbon dioxide. It diversifies agricultural activity and
recuperates deforested areas.
Disadvantages of the use of biofuels
The large extent of land needed. Negative effects on the fertility of the
soil, loss of biodiversity and destruction of
the landscape. Problems arising from the use of water
and agrochemical products. Increase in the price of primary
foodstuffs.