The Inter-Relationships of chemistry

Redox Chemistry

Redox (reduction/oxidation) chemistry deals with chemical reactions in terms of electron transfer

Reduction Reactions

Reduction reactions were originally associated with a loss (reduction) of mass in metal ores upon heating or reacting with carbon

Oxidation Reactions

Oxidation reactions were originally associated with the reaction of metals with oxygen

The substance that loses electrons is said to be oxidized

The substance that gains electrons is said to be reduced

Oxidation Number

Balancing redox equations

electrochemical cell

Electrochemical cells (also called galvanic cells or voltaic cells) are devices used to generate electricity

Electrodes

ANODE

ANIONS were defined as substances that moved towards the ANODE

The ANODE is always the site of oxidation

CATHODE

CATIONS were defined as substances that move toward the CATHODE in any cell

The CATHODE is always the site of REDUCTION

Half reactions

Cell Potential

Every combination of half cells will produce a unique electrochemical cell potential

Hydrogen Half Cell

There are hundreds of possible combinations of half-cells, each with unique voltages

Electrolytic Cells

Electrolysis is the splitting of stable compounds using an electric current

Electroplating

Electroplating uses an electric current to deposit metals at a cathode from a solution of aqueous metallic ions

Electrolysis

Electrolysis is the passing of a direct electric current through an electrolyte producing chemical reactions at the electrodes and decomposition of the materials

Agents

Oxidation Agent

reducing agent

Organic compounds

members of a large class of gaseous, liquid, or solid molecular compounds whose molecules contain CARBON

Alkanes

Saturated hydrocarbons because they contain more than the maximum amount of H bonded to C

Double bonds

Alkynes

Unsaterated

because they contain less than the maximum amount of H bonded to C

Triple bonds

Alkenes

Unsaturated hydrocarbons because they contain less than the maximum amount of H bonded to C

Cyclic

Alkanes and alkenes can commonly form rings.

Bonding capacity

Number of electrons out of the orbit

Hydrocabons

HYDROCARBONS are organic compounds containing only carbon and hydrogen

ALIPHATIC

Open chain

AROMATIC

Ring shape

aromatics

Amino acids

Isomers

ISOMERS are compounds with the same formula but different structures

Geometric Isomers

when 2 compounds contain atoms bonded in the same order, but they have a different spatial arrangement

Functional groups

Alcohols

Molecules containing the R-OH group (hydroxyl) are called alcohols

Aldehydes

Both aldehydes and ketones contain the carbonyl functional group

End of chain

Ketone

Middle of chain

Carboxylic acids

When a hydroxyl (C-OH) and carbonyl (C=O) are on the same carbon, a carboxylic acid is formed

Functional groups 2

Ethers

Ethers have an oxygen between two carbons (R-O-R).
They are volatile liquids used as solvents, anaesthetics.

Esters

Esters have an oxygen between two carbons (R-O-R)., however carbon-1 also has a carbonyl (C=O)
They are volatile liquids and are found in fruit flavours

Amines

Amines are classified as primary, secondary or tertiary depending on the number of alkyl groups (R groups) bonded to the nitrogen.

Tertiary

longest chain with N attached

secondary

Secondary amines are named using a different system

Amides

The amide has a structure similar to the ester however the oxygen atom

polymers

arge molar mass formed by the reaction of smaller molecule called monomers

addition

condensation

These are formed by reactions between an acid and alcohol

polymerization

A chemical reaction that bonds many monomers together to form a polymer

System and Surroundings

system is the sample being observed

surroundings is everything else

Reaction Enthalpy

Energy change associated with a reaction/transformation given certain conditions

Molar Enthalpy

Energy change associated with the reaction/transformation given ONE mole of a substance

Enthalpy

Enthalpy (heat content, H) is the total energy possessed by a system

Bond Energy Method

A chemical reaction can be viewed as a series of bonds breaking and reforming

Calorimetry Method

an experimental technique for measuring energy change in chemical reactions

Heat Capacity

Amount of heat required to change The temperature

Hess’ Law

Another way to determine ΔH is to utilize the concept that the overall enthalpy change of a system

Enthalpy calulations

Additivity method

Summation method

Rate of Reaction

The study of the rate or “speed” of a chemical reaction

Collision theory

Collision Geometry

Even if molecules with sufficient energy collide, a reaction may still not take place

The reactants must collide with sufficient energy for a reaction to occur

Reaction Mechanisms

Zero-order Reactants

The reactant concentration does not affect the rate

Elementary (Single) Step Reactions

reactions that only involve single events where bonds break and reform

Multistep reactions

Many reactions occur as a series of simpler elementary steps.

Molecularity

Molecularity is the number of particles (molecules or ions) involved in an elementary step

Factors affecting rate of reaction

Temperature

Catalysts: A catalyst is a substance that changes the rate a reaction without being consumed

Homogeneous catalyst

Ex. Food oils

Heterogeneous catalyst

Adsorption

Ex. uv radiation

Enzymatic Catalyst

Inhibitors:

Proteins

Surface area

Pressure

Equilibrium

At equilibrium, reactions actually take place in both the forward and reverse directions at the same time

Spontaneous Reactions

A spontaneous reaction is a reaction that favors the formation of products at the conditions under which the reaction is occurring

Equilibrium Systems

eactions actually take place in both the forward and reverse directions at the same time

Entropy

Systems tend to move spontaneously toward a state of maximum randomness or disorder

Dynamic equilibrium

dynamic equilibrium is disturbed by changing the conditions

Disorder

the greater the disorder the higher the entropy

Enthalpy

Enthalpy changes favour the exothermic direction of a reaction since these involve products with lower potential energy

Le Chatelier’s Principle

a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change to reestablish an equilibrium

K Value

Dependant on tempature

Concentration-Time Graphs

The Equilibrium Law Expression

Rice Tables

Solubility Equilibrium

Solubility Product

Dissolving

Crystallizing

Saturated Solutions

KSP

Reaction Quotient

equilibrium constant equation is solved under potentially non-equilibrium conditions, this “trial” calculation is called reaction quotient.

Formation of a Precipitate

Rice ( reaction, Initial, change, equilibrium)

Acids and bases

Arrhenius Theory

Arrhenius Acids

substances that dissociate to form hydrogen ions

Arrhenius Bases

substances that dissociate to form hydroxide ions

Brønsted-Lowry Theory

BL Acids

protons donors in a reaction

Subtopic

BL Bases

Subtopic

proton acceptor in a reaction

Lewis Acid-Base Theory

Lewis Acid

an electron pair acceptor. Cations or species with incomplete octet are Lewis acids.

Lewis Base

an electron pair donor. Anions or other species with lone pairs are Lewis bases

Weak Acids

Weak acids do not completely ionize

Logarithmic Function

opH and pOH Scales

KA Calculations

KB Calculations

Titration Curves and Buffers

Acid-Base Neutralization

Titration Calculations

Daltons atomic theory: reintroduced the atomic theory based on the available evidence

Thomson´s model of atom proposed the plum pudding model: a sphere of positive electrical charge in which electrons are embedded

Rutherford´s nuclear atom: all positive charge and most of the mass is concentrated in the nucleus of the atom. The electrons are found in the empty space around the nucleus.

atoms or elementary particles themselves are not real, they form a world of potentialities or possibilities

All electromagnetic radiation is made up of electric and magnetic fields

proposed that electrons exist as matter waves around the nucleus, with only complete integer values of the electron wavelength permitted.

Exact positions of electrons cant never be determined

probability distribution for where an electron may be found

p Orbitals

d Orbitals

f orbitals

Subtopic

Hydrogen obritals

A Lewis acid is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base

Positively and negatively charged ions either attracting protons orelectrons

electrostatic attraction between two charged particles

Greater nuclear charge pulls electrons closer to the nucleus

Valence Shell Electron Pair Repulsion

A theory used to predict the 3-dimensional geometry of molecules

AXE Notation

AXE Notation simplifies the identification of VSEPR shapes

Molecular Orbitals

VSEPR Theory was based on experimental evidence (electro densities).

Electrostatic Potential

A map of electrostatic potential measures the force acting on proton due to the molecule’s distribution of electrons/protons

Inter-molecular

Bonds within a molecule (covalent or polar covalent)

Intra-molecular

Bonds between molecules

London forces form due to the attraction between instantaneous dipoles

Compounds without bond dipoles only have London Forces between molecules (low melting points)

Compounds with bond dipoles and molecular dipoles Gives higher boiling points

ionic

Solids formed by ionic bonds between metal cations and non-metallic anions

Metallic

Metal properties can be explained by considering them as positive ions

covalent network solids

Form a lattice of continuous covalent / polar-covalent bonds

Paramagnatism: weak attraction

Diamagnetism: Repel

Ferromagnatism