Exam Flashcards
Organic Chemistry
The study of carbon based compounds
Hydrocarbons
an organic compound that contains only carbon and hydrogen atoms in it molecular structure
Alkane
a hydrocarbon with only single bonds between carbon atoms
Alkene
a hydrocarbon that contains at least one carbon-carbon double bond
Alkyne
a hydrocarbon that contains at least one carbon -carbon triple bond
Aromatic
a compound with a structure based on benzene: a ring of six carbon atoms
Alcohols
an organic compound characterized by the presence of a hydroxyl functional group; R-OH
primary alcohol
an alcohol in which the hydroxyl functional group is attached to a carbon which it itself attached to only one other carbon atom
secondary alcohol
an alcohol in which the hydroxyl functional group is attached to a carbon which is itself attached to two other carbon atoms
tertiary alcohol
an alcohol in which the hydroxyl functional group is attached to a carbon which is itself attached to 3 other carbon atoms
Ethers
an organic compound with two alkyl groups attached to an oxygen atom; R-O-R
An alcohol + alcohol =
an ether + H2O dehydration
Ketones
an organic compound characterized by the presence of a carbonyl group( C=O ) bonded to two carbon atoms
2o alcohol oxidized forms
a ketone
Aldehydes
an organic compound characterized by a terminal carbonyl functional group; carbonyl group bonded to at least one H atom ( H-C=O)
1o alcohol oxidized forms
an aldehyde
Carboxylic Acids
one of a family of organic compounds characterized by the presence of a carboxyl group; -COOH
Esters
an organic compound characterized by the presence of a carbonyl group bonded to an oxygen atom
esterification
a condensation reaction in which acid and alcohol combine to produce ester and water
Amines
an ammonia molecule in which one or more H atoms are substituted by alkyl or aromatic groups
alkyl halide + NH3 =
amines
Amide
an organic compound characterized by the presence of a carbonyl functional group C=O bonded to a nitrogen atom
acid + amine =
aminde
Saturated Hydrocarbon
contain single covalent bonds
unsaturated hydrocarbon
contain atleast one double or triple bond.
IUPAC
International Union of Pure and Applied Chemistry
Naming Alkanes
-Suffix ane
-The prefix indicates the number of carbons in the longest chain
-When naming closed ring hydrocarbons the prefix cyclo is used
Naming Alkenes and Alkynes
- suffix ene or yne
→ the presence and location of multiple double bonds or triple bonds is indicated by the prefixes di-, tri- etc.
Naming Benzene
if a benzene ring is attached to a large molecule it is considered a phenyl group
Naming Alcohol
-suffix -ol and is added to the prefix of the parent alkane
Ex. the simplest alcohol is methanol
→ 1o, 2o, 3o
Ex- 1- butanol, 2-butanol, 3-butanol
Naming Ethers
→ adding prefix oxy
→ small chain oxy large chain
→ CH3CH2-O-CH2CH2CH3 ( ethoxypropane)
Naming Aldehydes
→ formed by taking the parent alkene name, dropping the final -e and adding the suffix - al.
→ Methane is methanal
Naming Ketones
→ replacing the -e ending and adding the suffix -one
Naming Carboxylic Acid
→ take the name of the alkane or alkene with the same number of carbon atoms as the longest chain in the acid. The -e is replaced with the suffix -oic, followed by the word acid.
→ HCOOH: methanoic acid
→ aldehydes oxidizes to form carboxylic acid
Naming Esters
→ First part of name comes from the alkyl group of the alcohol used in the esterfication reaction
→ The second comes from the acid where -oic is changed to -oate
→ ethanol + butanoic acid form ethylbutamoate
Naming Amines
-a nitrogen derivative of an alkane would be aminomethane
an alkyl derivative of ammonia would be methylamine
→ depending where the amino group is it will be named 2-aminobutane
→ 2o amine has a N in the name when two carbon atoms are bonded to the Nitrogen atoms
→ 3o amine has N,N when 3 carbon atoms are bonded to the nitrogen atom
Naming Amides
the suffix ends in amides
→ follows similar patterns to amines
Addition reaction
a reaction of alkenes and alkynes in which a molecule such as a hydrogen or a halogen is added to a double or triple bond
4 Types of Addition Reactions
- Halogneation ( Br2 or Cl2 )
- Hydrogenation( with H2)
- Hydrohalogenation ( with hydrogen halides ) H-Cl, H-Br
- Hydration ( with H2O ) Alekene into Alcohol
Markovinkov’s Rule
When a hydrogen halide or water is added to an alkene or alkyne, the hydrogen atom bonds to the carbon atom within the double bond that already has more hydrogen atoms. “The rich get richer”
Subsitution reaction
a reaction in which a hydrogen atom is replaced by another atom or groups of atoms ; reactions of alkanes or aromatics with halogens to produce organic halides and hydrogen halides
Structural Isomers
a compoundwith the same molecular formula as another compound but different molecular structure.
Geometric Isomers
Cis vs Trans
- Same side of a double bond vs opposite
Why is Benzene Stable
The six carbon atoms form a perfectly regular hexagon. All of the carbon-carbon bonds have exactly the same lengths - somewhere between single and double bonds. There are delocalized electrons above and below the plane of the ring, which makes benzene particularly stable.
Functional Groups in order of boiling points, least to greatest.
Alkanes > Alkenes > Alkynes > Haloalkanes > Ether > Ester > Amine > Aldehyde > Ketone > Alcohol > Carboxylic Acid > Amide
Soluble functional groups
Alcohols, aldehydes, amides, amines, carboxylic acid, esters, ethers, ketone and nitriles containing up 1-5 carbons are water soluble.
Non-polar organic compounds
Hydrocarbons are always non-polar.
Monomer
a molecule of relatively low molar mass that is linked with other similar molecules
Polymer
a molecule of larger molar mass that consist of many repeating subunits called monomers
3 Steps of Polymerization
Initation
Propagation
Terminantion
Success and Failures of Bohr
Success: Explained Mendeleev’s periodic law ( elements are arranged in increasing atomic numbers, and chemical properties repeat in a patterned, predictable way ). Explained the spectra for hydrogen very well.
Failures: It only worked for hydrogen and went worse as atomic # increased.
Success and Failures of Rutherfords
Success: Declared that all the mass and positive charge is concentrated in the nucleus. Negatively charged electrons orbited like planets. There is a strong nuclear force that binds positive protons together. Gold Foil Experiment.
Failures: An accelerating charged particle will emit EM radiation. With EM the particle will eventually slow down and collapse into the nucleus. Which Rutherford could not explain.
Emissions Spectra
Emissions: corresponds to the excitation dark
Absorption Spectra
corresponds to relaxation
colourful
Principal Quantum Number
→ Main energy level of electron
→ Variable n
→ Range from 1-4
Secondary Quantum Number: Shape of Orbital
→ Sublevel in each energy level
→ Variable l
→ for each n value there is same number of subshells
→ Ranges from 0s, 1p, 2d …
→ n -1
Magnetic Quantum Number: Orientation in 3D space
→ variable ml
→ range from -l to - +l
Spin Quantum Number
→ Variable ms
→ two possible spins +½ and - ½
Energy Level Diagrams
1s
2s
2p
3s
3p
4s
3d
4p
Ion Charges for Electron Configurations
Zn2 vs Zn
Zn: [Ar] 4s23d10
Zn2+: [Ar] 3d10
Anomalous Configurations ( Cu and Cr )
Electron gets promoted into the 3d subshell to become more stable, as halffilled and filled are more stable than unfilled
Orbits
2D paths / 3D shells around the nucleus
Fixed path around the nucleus
Circular
2n2
Orbitals
3d spaces
No distinct shape
Only contain 2e-
Paramagnetism
→ weaker magnetic substance
→ due to unpaired electron spins
→ DOMAINS can not form in these substances
Valence Bond Theory
→ Partially filled electron orbitals will overlap so as to complete the pair
→ This leads to a decrease in potential energy and the formation of covalent bond
Sigma Bonds
-single bonds
-end to end
- rotation allowed
Pi Bonds
- double or triple bonds
- overlap
-no rotation
Hybridization
defined as the concept of mixing two atomic orbitals to give rise to a new type of hybridized orbitals
Lewis Structure
Step 1: Use the last digit of the group number from the periodic table to determine the number of valence electrons for each atom
Step 2: Place one electron on each of the four sides of an imaginary rectangle enclosing the central atoms before pairing electrons
Step 3: If there are more than 4 valence electrons, pair up electrons as required to place all valence electrons
Step 4: Use unpaired electrons to bond additi
VSEPR Theory and Importance
Valence Shell Electron Pair Repulsion: pairs of electrons in the valence shell of an atom stay as far apart as possible to mimimize the repulsion of their negative charges
→Only the valence shell electrons of the central atoms are important for molecular shape
→ the molecular shape is determined by the positions of the electron pairs when they are a maximum distance apart
4 bonding pairs, 0 lone pairs
Tetrahedral
3 bonding pairs, 1 lone pair
Pyramidal
2 bonding pairs, 2 lone pairs
Bent
1 bonding pair, 3 lone pairs
Linear
3 bonding pairs, 0 lone pairs
Trigonal planar
5 bonding pairs, 0 lone pairs
trigonal Bi-pyramidal
4 bonding pairs, 1 lone pair
Sea-saw
3 bonding, 2 lone
T-shape
2 bonding, 3 lone
Co-linear
6 bonding, 0 lone
Octahedral
5 bonding, 1 lone
Square Pyramidal
4 bonding, 2 lone
Square Planar
Polar Bond
a polar bond results from a difference in electronegativity between the bonding atoms: one end of the bond is, partially positive and the other end is equally negative.
Non-polar bond
a non-polar bond results from a zero difference in electronegativity between the bonded atoms
Polar covalent
a bond in which electrons are shared unequally
Polar molecule
a molecule that has polar bonds with dipoles that do not cancel to zero
Nonpolar Molecules
a molecule that has either non polar bonds or polar bonds whose bond dipoles cancel to zero
Difference Between Cohesion Vs Adhesion
Adhesion and cohesion are important water properties that affects how water works everywhere, from plant leaves to your own body. Just remember… Cohesion: Water is attracted to water, and Adhesion: Water is attracted to other substances.
London
→ The weakest intermolecular force
→ Temporary displacement of electron could create weak dipole dipole forces
→ Important in non-polar molecules but present in all molecules
→ Bigger the molecules stronger the forces
Dipole Dipole
→ Second strongest force
→ Force of attraction between oppositely charged ends of any polar molecule
Hydrogen Bonding
→ Strongest force
→ Strong dipole dipole force only in molecules with F-H, O-H, N-H
Highest and Lowest Boiling Points of Different Compounds Based on Intermolecular Forces
Properties
Stronger force - Higher melting and Boiling Points
Weaker force- Lower melting and Boiling points
Ionic Crystals
→ Crystal Lattice of alternating - and + ions
→ High melting points
→ Hard, Brittle
→ Highly Soluble in Water
→ Electrolytes
→ Complete transfers
Metallic Crystals
→ positive nuclei surrounded by loosely held valence electrons
→ creates delocalized sea of electrons
→ Lustrous: valence electrons absorb and reemit many wavelengths of light
→ Malleable, ductile
→ Hard and Dense
→ Crystalline: electrons act as glue
→ Conducts heat
→ Electrons are shared equally
Molecular Crystals
→ Soft
→ Low melting point
→ Non-electrolytes
→ Molecules held together by weak molecular forces
→ Electrons flow around
Covalent Network
→ very hard and brittle
→ very high melting point
→ non-electrolytes
→ diamond
→ covalent bonds exist between each molecule
Pauli’s Exclusion Principle:
no 2e- of an atom can have the same set of quantum #’s
Aufbau Principle
each electron is added to the lowest energy moving up to the higher energy orbitals
Hund’s Rule
Electrons must be spread out as much as possible before moving up
Law of Conservation of Energy
Energy is not created or destroyed but merely changes forms, going from potential to kinetic to thermal energy.
Q = mc△ t
m= mass
c= special heat capacity ( quantity of heat required to raise the temperature of a unit mass of a substance 1 oC or 1K.)
Q = the quantity of heat transferred
Open System
one in which both matter and energy can move in or out
Closed System
one in which energy can move in or out, but not matter
Kinetic vs Potential Energy
Potential Energy: The stored energy in any object or system by virtue of its position or arrangement of parts.
Kinetic Energy: The energy of an object or a system’s particle in motion.
5 Factors that affect the rate of reaction
The Concentration of the reaction
Temperature
Physical State of reactants
The presence of a catalyst
Light
Collision Theory
for a chemical reaction to occur, the reacting particles must collide with one another.
3 Assumptions in Calorimetry:
1 - no heat is transferred between the calorimeter and the outside environment
2 - any heat absorbed or released by the calorimeter materials, such as the container, is negligible
3 - a dilute aqueous solution is assumed to have the density and specific heat capacity equal to that of pure water ( 4.18 kj/kg oC )
Isolated System
an ideal system in which neither matter nor energy can move in or out
System vs Surrounding
The system is always defined as the reaction and the surroundings are essentially considered to be everything that is not directly involved in the reaction.
Molar Enthalpy Change Calculations
△H = n△Hvap
Thermochemical Equations ( 3 ways)
Method 1: Energy Terms
With an exothermic reaction the energy term must be a product.
2 C4H10 + 13 O2 → 8 CO2 + 10 H2O + 5742 kJ
With an endothermic reaction the energy term must be a reactant side.
AgNO3 + 22.6 kJ → Ag+ + NO3-
Method 2: △H Values
CO + 2H2 → CH3OH △H= -128.6 kJ
The units for enthalpy change are kJ to kJ/mol, because the enthalpy change applies to the reactants and products as written, the moles must be taken into consideration. The same reaction could be written as
½ CO + H2 → ½ CH3OH △H = -64.3 kJ
Method 3: Enthalpy Diagram
Bond Energies
△H rxn = reactents - products
Hess Law
The amount of heat involved in producing one chemical from another is always the same, no matter how many stages are taken to obtain the desired product.
Why is Hess’s Law Used
It allows us to combine equations to generate new chemical reactions whose enthalpy changes can be calculated, rather than directly measured.
Write Formations of Equations
Standard Enthalpy of Formation: the quantity of energy associated with the formation of one mole of a substance from its elements in their standard states
Step 1: Write one mole of product in the state that has been specified
Step 2: Write the reactant elements in their standard states
Step 3: Choose equation coefficients for the reactants to give a balanced equation yielding one mole of product
△H = ∑ n△Hof( products) - ∑n△Hof( reactants)
Rate of Reaction
the speed at which a chemical change occurs.
Average Rate of reaction
the speed at which a reaction proceeds over a period of time
* To find on a graph, the average over a time period is the absolute value of the slope of secant drawn between two points
r = △c/ △t
Instantaneous Rate of Reaction
The speed at which a reaction is proceeding at a particular point in time
Rate Law
The relationship among rate, the rate constant, the initial concentration of reactants and the orders if reaction with respect to the reactants
R = K [X]m[Y]n
Order of Reactions
M or N To find those values is through experiments.
0 means substance concentration has no effect on the rate
1 if you x2 [a] it will double the rate
2 if you double [a] it will quadruple the rate
If you tripe it will x9 the rate
Calculate the Overall Order of Reaction
The overall reaction order is simply the sum of orders for each reactant. For the example rate law here, the reaction is third order overall (1 + 2 = 3). Adding the m + n exponents values together.
Calculate Amount of Energy Using Missing Mass
Einstein: mass can convert to energy
E= mc2
C2 = speed of light ( 3.0 x 108m/s)
Balance Nuclear Equations
Nuclear reactions cause various forms of radiation
Alpha Particle: 24He
Beta: -10e
Gamma Ray: 00y
Importance of Nuclear Binding Energy
The nuclear binding energy is the energy that holds the nucleus together. Binding energy is necessary to split subatomic particles in atomic nuclei or the nucleus of an atom into its components namely: neutrons and protons or collectively known as the nucleons.
Elementry Steps
a step that only involves 1,2 or 3 entity collisions that cannot be explained any simpler
Unimolecular
A reaction, mechanism step, or other process involving only one molecule.
Bimolecular
A reaction, mechanism step, or other process involving two molecules.
Termolecular
sequential bimolecular reactions where two reactants form an initial complex and the complex then reacts with the third reactant.
Rate Determining Step
the step in the reaction mechanism that determines the rate of the overall reaction: slowest step
Heat
the amount of energy transferred between substances
Exothermic
releasing thermal energy as heat flows out of the system (-)
Endothermic
absorbing thermal energy as heat flows into the system (+)
Temperature
Average kinetic energy of the particles in a sample of matter
Quantitative Reaction
a reaction in which virtually all of the limiting reagent is consumed
Equilibrium Reaction
when the rate of the forward reaction equals the rate of the reverse reaction
Ke
Equilibrium Constant: Ke → the value obtained from the mathematical combination of equilibrium concentrations using the equilibrium law expression.
aA + bB ⇆ cC + dD
K = [C]c[D]d / [A]a[B]b
Le Chatelier’s Principle
When a chemical system at equilibrium is disturbed by a change in a property, the system adjusts in a way that opposes the change.
Equilibrium Shift
movement of a system at equilibrium, resulting in a change in the concentration of reactants and products.
Add a Reactant
( Favors the Product)
Remove Reactant
Favors reactants
Add or Remove a product
( Favors the reactant )
Change Volume
pressure is inversely proportional to the volume
If Volume increase Pressure Decreases
P1V1 = P2V2
Change in Temperature
Endothermic reactions the products are favored
Increase will cause a shift to the right
Decrease will cause a shift to the left
Addition of a catalyst
speed up rate of forward reaction but has no effect on the equilibrium
Insert gas
increases pressure
Pressure ( adding or removing)
if pressure is added, shift towards the side with less moles. If pressure is relieved shifts towards the side with more moles
Homogeneous vs Heterogeneous
Homogenous System: All components are in gaseous solution or phase
Heterogeneous System: Components differs in their states
Calculating Qt Value and Equilibrium Shift
Qt reaction quotient: a test calculation using measured concentration values of a system in the equilibrium expression
Q=K system is at equilibrium
Q is greater than K the system must shift left
Q is less than K the system must shift right
Solubility vs Solubility Product
Solubility: the concentration of a saturated solution of a solute in a particular solvent at a particular temperature; specific maximum concentration
Solubility Product Constant ( Ksp ): the value obtained from the equilibrium law applied to a saturated solution
Determine If Precipitate Will Form
Q> Ksp precipitate forms
Q < Ksp precipitate does not form
Strong and Weak Acid
Strong Acid: an acid which completely ionized in an aqueous solution (HCl)
Weak Acid: an acid that ionizes only slightly in an aqueous solution ( Acetic Acid )
Strong and Weak Base
Strong Base: a base which is completely ionized in a solution.
Weak Base: a base that ionizes only slightly in a solution.
Where Hydronium Ion Comes From
The hydronium ion always forms when an acid dissolves in water. The H+ from the acid always goes to the nearest water molecule and forms H3O+.
Identify Conjugate Pairs For Acids and Bases
In the Brønsted–Lowry definition of acids and bases, a conjugate acid–base pair consists of two substances that differ only by the presence of a proton (H⁺). A conjugate acid is formed when a proton is added to a base, and a conjugate base is created when a proton is removed from an acid.
An acid is a proton donor ( donates an H+ ) Ion
A base is a proton receiver ( receives a H+) Ion
The stronger the acid the weaker the conjugate base, and conversely, the weaker an acid, the stronger its conjugate base.
Determine Ph or POH of H3O
pH= -log[H+]
POH= -log[OH-]
14-(-log[OH-]) = pH
Purpose of Buffer
Buffer: a mixture of a conjugate acid-base pair that maintains a nearly constant pH diluted or when a strong acid or base is added: an equal mixture of a weak acid and its conjugate base.
The main purpose is to maintain the pH level to a certain value by neutralizing the small amount of acid or bases added to that particular solution by making them a weak acid or base.
Ionization Percentage
p= concentration of acid ionized/ concentration of acid solution x 100%
