water, molecular interactions, and acid-base chemistry Flashcards
dipolar nature of water
hydrogen atoms have localized partial positive charges and the oxygen atom has a partial negative charge
what is the structure of water
tetrahedral arrangement of electron pairs and hydrogen atoms around oxygen atom
hydrogen bonds
longer and weaker than covalent O-H bond
what is a hydrogen bond defined by?
defined by distance between acceptor and donor
how many hydrogen bonds are possible per water molecule?
four hydrogen bonds; where in liquid water average 3.4 H bonds and ice all 4 H bonds
why does ice have all 4 H bonds?
allows it to be more opened up, resulting in its density being less than liquid water
what is important for clathrate-like structures?
entropy effect
what is the lifetime of a hydrogen bond?
1-20 ps (10^-12 s); liquid water can be described as a “flickering structure”
hydrogen bond donors
N-H, O-H (not C-H)
hydrogen bond acceptors
N: and O:
what differentiates a functional folded protein from a precipitated protein?
only 10 kJ/mol
what is a factor for the strength of a hydrogen bond?
stronger when 3 atoms involved like in a line
amphipathic
both hydrophilic and hydrophobic
what are some of the characteristics of long-chain fatty acids?
very hydrophobic alkyl chains surrounded by a layer of highly ordered water molecules
what stabilizes the micelle?
energy gained by freeing immobilized water molecules
