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Hydrocarbon
compound composed of only carbon and hydrogen
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Saturated Hydrocarbons
compound with only single bonds
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Unsaturated Hydrocarbons
compounds with at least one double or triple bond
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Alkane
compound composed of only carbon and hydrogen and single bonds
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Acyclic Alkanes
compound composed of carbon and hydrogen in a chain-like conformation
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Cycoalkane
cyclic compound containing only carbon and hydrogen
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Heteroatoms
- atoms in a molecule that are not carbon or hydrogen
- cyclic structures with heteroatoms = heterocycles
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Hybridization
combination of atomic orbitals to form new (hybrid) orbitals of different shapes and orientations
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how are bond distance and stability related?
the shorter the bond the more stable it is
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carbons bonded to four atoms undergo what kind of hybridization?
sp3 hybridization
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carbons bonded to three atoms undergo what kind of hybridization?
sp2 hybridization
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carbons bonded to two atoms (+ triple bond) undergo what kind of hybridization?
sp hybridization
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Branched alkanes
alkanes that have carbon that are bonded to more than two carbons (aka skeletal isomers)
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Alkyl Group
hydrocarbon chain with one open point of attachment (often R is used to describe a generic alkyl group)
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Conformational Isomers
isomers that differ as a result of the degree of rotation around a carbon-carbon single bond
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Staggered
conformation around a carbon-carbon single bond in which attached atoms are as far apart as possible
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Eclipsed
conformation around a carbon-carbon single bond in which attached atoms are as close together as possible
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Torsional/Dihedreal Angle
angle between the bonds in the newman projection (aka end on end projection drawing)
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Potential Energy Diagram / Reaction Coordinate Diagrams
a graphical depiction of energy changes during a chemical reaction
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Transition State
- maximum in a potential energy diagram
- a dynamic process of change in which bonds are being broken and formed in a reaction
- eclipsed form can be viewed as the transition state between two staggered forms
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Energy Barrier
energy needed to go over a transition state
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Energy of Activation
the energy difference between reactants and a transition state
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Heat of Reaction
- the difference in energy between the reactants and the products
- endothermic vs. exothermic
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Catalysts
a reagent that influences the course and rate of a reaction without being consumed
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the two different kinds of staggered forms?
- Anti and Gauche
- anti is the most stable
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Isomers
compounds with the same molecular formula but different structures
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Skeletal Isomer
compounds that differ in their carbon skeleton
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Functional Group Isomer
compounds containing different functional groups
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Positional Isomers
when the position of the functional group differs
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Fused Ring Systems
when several cycles/rings share two common atoms and the bond between them
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Spiro Compound
when two rings share one carbon
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Bridged Ring Compounds
two rings share two non-connected atoms, thereby building a bridgehead with the two atoms
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What position do bulky substituents prefer in a substitute cycloalkane?
equatorial position (NOT axial)
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Geometric Isomers
when atoms/groups display different orientation differences around a double bond/ring
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Cis Isomer
groups are on the same side of a ring/double bond
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Trans Isomer
groups are on opposite sides of a ring/double bond
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4 Properties of Alkanes
- melting and boiling points increase as molecular weight increases
- Boiling point decreases with chain branching BUT melting point increases
- non-polar substances = not soluble in water
- alkanes are less dense than water, so they swim on top of it
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What is the cracking process?
fractional distillation of crude oil by boiling at different temperatures to separate alkanes
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Two types of reactions that can be done with Alkanes
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What is Halogenation
substituting one atom for a Halogen (chlorination, bromination, etc)
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How to control the degree of halogenation?
by controlling the percentages of the alkane and the halogen
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3 Properties of Haloalkanes
- toxic and cause cancer
- Major component of free radicals in ozone layer
- polar bond (partial charges)
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Bronsted Acid
acid that is a hydrogen ion donor in chemical reaction
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Bronsted Base
base that can accept protons during a reaction
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Strong Acid
- acid that is 100% ionized in a water solution
- HCl, Her, H2NO3
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Weak Acid
- acid that is only partially ionized in water solutions
- H3C-CO2H
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The relationship between pKa and acidity?
the lower the pKa, the stronger the acid
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Conjugate Base
species formed by loss of a proton from an acid
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Conjugated Acid
species formed by gain of proton by a base
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Lewis Acid
- a substance that can accept a pair of electrons for sharing from a Lweis base in a chemical reaction
- electrophiles are lewis acids
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Lewis Base
- a substance with an outer-shell non-bonding electron pair that is can share in a chemical reaction with a Lewis Acid
- nucleophiles are lewis bases
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