Intermolecular Bonding + Water's Importance Flashcards
Intermolecular Forces Def.
Attractive forces between molecules. Influences properties such as melting/boiling point. Weaker then intramolecular
Intramolecular Forces Def.
Forms atoms in a molecule
What does intermolecular forces influence on boiling/melting point mean
Controls matter state
Dipole Def.
When a molecule has a delta negative atom and a delta positive atom
Relationship between dipole and electronegativity
Higher electronegativity = greater dipole
Polarity unit of measurement
Debye (D)
What type of molecules have no dipole moment (0D)
Non-polar (eg atoms of the same element)
What type of molecules do have a dipole moment
(>0D)
Polar
What influences a dipole moment
Bond polarity and molecule shape
Position of dipoles from eachother in linear molecule
Opposite ends of molecule = non-polar . 0D as electron flow moves left and right from least electronegative atom equally (balance)
Position of dipoles from each other in bent molecules
Angles greater/less then 180 degrees from each other. Polar >0D
Dipole-dipole forces Outline
Occur between polar molecules. The bigger the dipole moment = the greater the force
Ion - Dipole Forces Outline
Occur between an ion and a polar molecule. The bigger charge + atomic radius size of ion and polar magnitude + dipole moment of molecule = greater force
How atom/ non-polar molecule has dipole induced by ion
Ion placed in vicinity in neutral/ non-polar molecule pushes electrons out of alignment
How a dipole induces qa dipole in an atom/non pola molecule
Proximity of dipole pushes electrons out of alignment
Factors That Influence Degree to Which Dipole is Induced
Ion charge/dipole moment size and polarizability of substance having dipole induced
Instantaneous Dipole Def.
atom/ non-polar molecule with high polarizability will develop a dipole moment at random times
H Bonds
Strongest intermolecular force. Dipole-Dipole between H (bond donor) and O, N or F (bond acceptor)
Instantaneous Dipole - Induced Dipole Outline
Instantaneous dipole induces dipole in it’s neighbours. Magnitude of attraction is proportional to atom/molecule polarizability
Ion to Ion (ionic bonding)
Electrostatic force. Forms lattice structures. Strong interactions take place between multiple ions
Dispersion Forces Variations
Can range from weakest form of intermolecular interaction to stronger then dipole-dipole
Why does water have a high boiling point
Held together by H bonding. Takes a lot of energy to break bonds
Specific Heat Capacity Def. (J/g)
Energy required to heat 1g of a substance by 1 degree C
Why do humans not vary in temperature that much
High specific heat capacity in water. Adult body is 60% water
Sickle Cell Anaemia Outline
Immune cells destroy irregularly shaped erythrocytes resulting in lack of gas exchange. Cell irregularity caused by difference of 1 amino acid in haemoglobin
Glutamic Acid
Amino acid in regular haemoglobin
Valine
Non-polar amino acid replaces glutamic acid in erythrocytes. When exposed in low O2 it forms a hydrophobic region. This causes haemoglobin molecules to precipitate forming irregular shapes
Why Hydrogen Bonds are important in body
DNA double helix (between base pairs)
How do drugs bind to active site
intermolecular forces
