What is the frequency and wavelength of a photon absorbed in the transition of an electron from the n=5 to the n=8 of dye #3 (1-1’-diethyl-2-2’-dicarbocyanine iodide).

to do this calculation, you will need to make a reasonable assumption for the value of l. as a first approximation, we will assume that the value of lcc in these molecules is the same as in benzene and pyridine, two similar delocalized systems: lcc = 0.140 nm (benzene) lcn = 0.134 nm (pyridine)

the aromatic rings capping the ends of the dye molecules complicate the unambiguous assignment of length. indeed, several reasonable choices are possible. one simple choice is assume the length of the molecule to be from one n atom to the other n atom. the effect of the rest of the aromatic rings is then considered to be absorbed into the parameter ‘p’ (equation 7). considering the information given above, estimate the value of ‘p’. ex: do you think the electron will penetrate far outside the nitrogen caps, or vice versa? (after comparing your predictions to the experiment, you will be able to derive a more accurate value for ‘p’.)

Straightforward questions answered in the powerpoint slidesreaction: heating the starting materials under refluxwhat does it mean to heat under reflux? why do we choose water as the reflux solvent? what are boiling chips used for? why do we put a condenser on top of the reaction? why do we add heat and let the reaction stir for 30 minutes? why do we add sulfuric acid to the reaction after it cools as opposed to when it’s still hot? separation: filtration of precipitatewhy don’t we do an aqueous and organic extraction in the separatory funnel? why do you rinse the salicylic acid on the filter with ice cold water? purification: recrystallization of salicylic acid (no hot filtration needed)what is the difference in the amount of room temperature water vs. boiling water needed to dissolve the salicylic acid (assume a 1.2 gram yield of salicylic acid)? remember, in the lab if you need x ml of boiling water to dissolve a solid, then you should add a little more (definitely no more than 1.5 times the theoretical amount) to ensure it doesn’t recrystallize prematurely.analysis: melting point of salicylic acidwhat can you conclude if the melting point of the salicylic acid you just synthesized is 152-155oc and the 1: 1 mix of your product and “synthetic” salicylic acid is 151-154oc?

Avolleyball player hit a ball with a mass of 0.25 kg. the average acceleration of the ball is 15.5 m/s². how much force did the volleyball player apply to the ball? 62.0 n 3.87 n 62.0 m/s² 3.87 m/s²

Why is it possible for different microorganisms to extract energy not only from carbohydrates and other biological molecules but from a large variety of substances?