Intermolecular Forces & Refraction

What are ions held together by

strong coulombic attractions

the closer the ion and dipole…

stronger the attraction

van der waals forces functions

• organic reactions between molecules

• how drugs may be formulated

• interactions betweem drugs and targets

types of van der waals forces

• dipole/dipole

• dipole/induced dipole

• induced dipole/induced dipole

whats a dipole/dipole attraction

when a polar molecule encounters another (or the same) polar molecule, the positive end of one is attracted to the negative end of the other

extreme form of dipole/dipole interaction

hydrogen bonding

the higher the molecular mass…

the larger the electron cloud and the greater the polarizability

what is refractive index

when light passes through substances slower than it does through a vaccum

how does refractive index work

the atoms absorb the energy from the light causinf the light waves to shorten and the speed to reduce

what is refraction

If light strikes a surface at an angle, the light becomes bent towards the perpendicular line to the surface

whats refraction measured by

the redractive index

2 refractive index variables

• wavelength of light

• temp

whats used to determine the refractive index

refractometer

what can a refractive index do?

• identify a substance

• be a measure of purity

• determine concentration of one substance dissolved in another