water and carbon Flashcards
what is the angle between oxygen and hydrogen
104.45
why is water polar?
oxygen is more electronegative than hydrogen. with polar covalent bonds. hydrogen is positive and oxygen is negative also making water a dipole.
implications of water being a dipole molecule
molecules attracted to each other
interact via hydrogen bonds
4 hydrogen bonds with other water molecules
hydrogen bonding network
good solvent for other polar molecules
how does hydrogen bonding occur?
slightly electronegative oxygen attracts slightly electropositive hydrogen causing attractive forces known as dipole-dipole interactions known as hydrogen bonds that are longer than covalent bonds
water interacting with a globular protein
nonpolar side chains point inward and interact with one another
polar polar hydrophilic amino acids bound outwards create dipole dipole interactions with solvent
creating solubility and stability
why water has good surface tension?
cohesive forces to neighbouring molecules due to the presence of hydrogen bonding creating a strong surface tension
why does flickering clusters happen in water?
most molecules in liquid water engage in hydrogen bonding, have a short life span and once one hydrogen bond breaks another reforms with the same partner or new. “ short lived groups of water molecules interlinked by hydrogen bonds in liquid water. great internal cohesion
ice
each hydrogen bond is attached to 4 other neighbouring molecules. ideal thermal conditions are never met. the molecules are further apart to achieve the configuration. hydrogen at maximum. lower density than water.
why is water a good solvent?
water dissolves salts (NaCl) by hydrating and stabilising the Na and Cl ions - weakening electrostatic interactions between them - counteracting tendency to associate in crystailine lattice
aromatic and aliphatic
aromatic- compound featuring delocalised ring of electrons
aliphatic- non aromatic- does not contain ring of electrons
carbon skeleton
4 covalent bonds ( H,O,N,S) linear chains, branched and cyclic structures consisting of carbon atoms a possible carbon skeleton. functional groups give rise to chemical activity.
simple hydrocarbons
meth- 1
eth- 2
prop- 3
but- 4
pent- 5
hex- 6
functional groups
polar - alcohols and thiols, aldehydes, ketones, carboxylic, amines , amides and esters ( all contain N, O or S) form hydrogen bonds with water, solubility in water hydrophilic
non-polar- aliphatic and aromatic may not contain N, O or S do not form hydrogen bonds with water, solubility in water hydrophobic
silicon-based life form
can form 4 covalent bonds
less stable
