Refresher Module Flashcards
What is organic chemistry?
study of structure, properties, and reaction software ORGANIC COMPOUNDS (carbon containing)
What are hydrocarbons?
simplest organic compound containing H + C in single bonds and no functional groups (alkanes and cycloalkanes)
What are functional groups?`
group of 1+ atoms whose STRUCTURE gives it particular PROPERTIES + predictable pattern of REACTIVITY
How can functional groups be identified?
π-bonds and heteroatoms
What are the 4 types of hydrocarbon functional groups? What are their properties?
Alkanes: not reactive bc all C-C and C-H sigma bonds)
Alkenes: contains double bond - π-bonds are weaker than sigma = more reactive = more functional
Alkynes: contains triple bonds (2π)
Aromatics: ring structure of alternative single and double bonds
What are heteroatoms? Why are they important for functional groups?
atoms besides H and C
- heteroatoms have 1+ Lone pairs so electron density around these atoms is different = effects physical properties and reactivity
What determines the intermolecular forces that are in a molecule?
structure (controls physical properties) bc of e- distribution
How does the strength of intermolecular forces compare to covalent bonds?
weaker than covalent bonds but are collectively strong enough to influence physical properties (melting, boiling points, solubility)
What is ELECTROSTATICS?
- strongest intermolecular force = ionic structures
- attraction between two molecules of opposite formal charge
What are DIPOLE-DIPOLE INTERACTIONS?
attractive force between the NEGATIVE end of a PERMANENT dipole in a molecule & the POSITIVE end of a PERMANENT dipole in another molecule
How does electrostatics and dipole-dipole interactions compare?
electrostatics is strongest (formal charge compared to delta + or -)
What is HYDROGEN BONDING? How does it’s strength compare?
- type of dipole-dipole interactions specific to delta + H atom as it is connected to electronegative atom (O or N)
- stronger type of dipole-dipole interaction because there is a greater difference between the electronegativities
What are hydrogen bonds donors and acceptors?
donor: hydrogen
acceptor: other atom H is attracted to
What are Dispersion (London) forces?
- exist in all molecules close to each other
- temporary dipoles created by electron repulsion
- weakest
How does the molecule size impact melting and boiling point?
longer chain = higher surface area = more intermolecular forces = more difficult to break bonds = higher melting and boiling points
How does the molecule branching impact melting and boiling point?
more branching = lower surface area = less dispersion force availability = easier to break bonds = lower melting and boiling points
How does ring structure impact melting and boiling point?
ring structure = packs well together = increase SA = increase intermolecular forces = more difficult to break bonds = higher melting and boiling points
How does the types of bonds generally impact melting and boiling points?
highest mp + bp: electrostatic force
h-bonding
dipole-dipole (permanent dipole)
lowest: London forces
What is solubility?
how well a solute (molecule) dissolves in a particular solvent
What is the relationship between the solute and solvent?
molecules are most soluble when the types of intermolecular forces are well matched between solute and solvent
What are the 3 main solvents?
- polar protic solvents
- polar aprotic
- non-polar
Wha are POLAR PROTIC solvents?
can act as H-bond donors and miscible in water
Wha are POLAR APROTIC solvents?
strong dipoles
many can act as H-bond acceptors
often highly soluble in water
Wha are NON-POLAR solvents?
generally held together by dispersion forces
not miscible in water
What are the properties/uses of water as a solvent?
- highly polar
- lab purification
- adding more non-polar groups decreases water solubility and vice versa
hydrophilic?
hydrophobic?
hydrophilic: ‘water loving’
- polar enough from favourable intermolecular forces
hydrophobic: “water fearing”
- only London forces
- not string enough to form/overcome intermolecular forces in water
How does branching impact solubility?
water h-bonds branched molecules better than unbranched (less dispersion forces) = increase solubility
How does charge impact solubility?
charged molecules interact with water by electrostatics = high reactivity = high solubility
formal charge calculations?
valence electrons - # bonds on that atom - # unshared e-
