Solutions & chromatography & spectroscopy

Question 1

what happens when we distill 2 liquids

Answer 1

the compound with the lower boiling point will vaporise first, so it becomes more prevalent in the solution and this is how we separate them (multiple distillation cycles)

Question 2

what is the formula for retention factor

Answer 2

distance traveled by solute/distance traveled by solvent

Question 3

what does a small Rf mean

Answer 3

more polar (toward the bottom, doesn’t travel much)

Question 3

what does a big Rf mean

Answer 3

less polar

Question 3

what is the difference between column chromatography and thin layer chromatography

Answer 3

thin layer, the less polarised moves up while column chromatography means the less polarised moves down (the more polarised substance will remain at the point of origin)

Question 3

what type of spectroscopy causes molecules to rotate

Answer 3

microwave

Question 4

what type of spectroscopy is used for vibration

Answer 4

infrared

Question 5

what happens when a molecule absorbs a photon of visible light

Answer 5

an electron in the molecule will move to a higher energy orbital

Question 6

what is the first ionisation energy

Answer 6

the energy required to get the outer most electron removed from a atom shell

Question 7

what happens when an electron moves from a 2p orbital to a 1s orbital

Answer 7

energy is lost

Question 8

what is the law for absorbance of light (beer lambert)

Answer 8

A = e[epsilon]bc

where A = absorbance, epsilon = molar absorbency, b = length of light & c = concentration (L)

Question 9

what formulae are used to calculate the energy of a photon

Answer 9

E = hv and v = c/lambda

where E = energy, h= planc’s constant, c = speed of light & lambda = wavelength

Question 10

what is the difference between intermolecular forces and intramolecular forces

Answer 10

intra keep the molecule together e.g. forces between atoms, and inter determine the physical structure because they’re attractions between molecules