u1 biochem Flashcards
(89 cards)
what are covalent bonds?
covalent bonds are bonds where two atoms share electrons to have a full, satisfied outer shell
what are polar covalent bond and non-polar covalent bonds?
polar covalent bonds are bonds between two or more atoms that share the same electrons unequally because 1 atom is more electronegative than the other so it has more pull for the electrons. one side of bond is more negative and other is more positive.
non polar covalent bonds are bonds between two or more atoms that share the same electrons equally. no charges.
what bond is it where the EN difference is <0.5
non-polar covalent
what bond is it where the EN difference is 0.5<EN<1.7
polar covalent
what bond is it where the EN difference is >1.7
ionic bond
what is hydrogen bond and explain its dipoles briefly
a force of attraction between a hydrogen atom and a more electronegative atom such as O, N, F.
Has very strong dipole interactions due to their electronegative properties.
ground state
The original state of electrons/energy at rest. This is the most stable arrangement
excited state
electrons absorb energy and jump to outer orbits
isotopes
atoms that have the same # of protons but different number of neutrons (which effects mass).
anion
the atom that receives an electron (becomes more negative)
cation
the atom that gives away an electron (becomes more positive)
what is electronegativity
electronegativity measures the power of an atom to attract bonding pairs of electrons.
why do non-polar molecules not dissolve in water
non-polar doesn’t dissolve in water because it doesn’t have dipoles to interact with water. hydrogen bonds are too strong to interfere with as well.
dipole-dipole vs vander waals
dipole-dipole IMF is permanent and there are charges.
vander waals or LDF is temporary and there are no charges.
what are compounds
two or more atoms
intermolecular vs intramolecular
inter. means forces WITHIN a molecule (eg. H giving e- to Cl)
intra. means forces between two or more diff. molecules. (eg. H2O bonding with OH)
5 properties of water
- high surface tension
- high specific heat
- low density at solid
- high heat of vaporization
- adhesion/cohesion
why is water a universal solvent
water is very polar, meaning it has one negative end and another positive end which helps it dissolve things (positive and negative charges attract other pos/neg charges)
what is the strongest bond and why
hydrogen bonds are the strongest because they have high electronegative difference which allows it to attract many electrons.
bc of the EN diff. where oxygen has high EN and hydrogen has low EN, O hogs the e- which results in a polar covalent bond with a neg end and a pos end.
what are the functional groups (needed for test)
hydroxyl (OH), amino (NH2), sulfhydryl (SH), carboxyl (COOH), carbonyl (COO)
hydroxyl
OH - makes things more soluble in water
structural isomer
two or more compounds that contain the same # of atoms but differ in geometric arrangement. (Same molecular formula different arrangement).
monomer
a molecule that can combined to others of the same kind to create larger, more complex structures
polymer
made up of many joined monomers