Chemical concepts Flashcards
functional groups, polarity and solubility
how does an increase in chain length impact alkanes?
increases liquid form
what role do aldehydes and ketones play in food?
aroma
how does the difference in the structure of chlorophyll a vs b change its wavelength on the visible spectrum? how is their functional group different?
chlorophyll a is more blue
- CH3 group
chlorophyll b is more green
- CH=O group
what type of bonds are covalent and ionic bonds? how are they formed? which is more stable?
intramolecular bonds
covalent: sharing of electrons
-more stable
ionic: bond between highly EN atoms
what is electronegativity?
attraction of an atom for the electron cloud that forms between 2 atoms
what is a dipole moment?
it is the magnitude of charge between either atom
how does a molecule become classified as polar?
by having a difference in EN
what are inductive effects?
the induced electronegative/positive effect from atoms attached to highly charged atoms
- causes a local change in electron density
what are ion dipole bonds?
an intermolecularattraction between an ion and a polar compound
-stronger than dipole dipole, weaker than covalent / ionic bonds
what are hydrogen bonds? are they stronger than ion dipole bonds?
the interaction between a hydrogen atom and a highly EN atom
- weaker than ion dipole
what are van der waal forces?
induced dipole that occurs as non-polar compounds interact with eachother
what is the dielectric constant? what values indicate what?
An indicator of polarity
- ability for a substance to insulate opposite charges from each other
-material’s ability to reduce the electric field between two charges, effectively “screening” the interaction (physics definition)
> 15 = polar
<15 = non polar
how does increased chain length for hydrocarbons impact polarity?
increased length decreases polarity
explain how carotenoids react in oil?
they are large and non polar and will partition into the oil phase
what is the partition coefficient? what do the numbers indicate?
the ratio of partitioning between 2 solvents; hydrophobic solvent / water often used
log P = 0 indicates 50:50 partitioning
log P <0 = increased partitioning in water phase (higher solubility)
log P > 0 = increased partitioning in lipid phase
how does the solubility of CO2 change in water?
it will be found as CO2 at pH 7 and below
-found as HCO3- @ pH 8-9
-found as CO3 2- @ pH >10
what is henry’s law? how is this important in the food industry?
the increased solubility as pressure increases
- important for carbonated beverages
explain the simple method for measuring CO2 in food:
1) CO₂ is released from a food sample and reacts with Ba(OH)₂ to form (BaCO₃)
2€‹⁄) The mass of BaCO₃ is directly proportional to the amount of CO₂ in the sample, enabling accurate quantification
