Question

5. What is the full numerical range of possible Rf values in a TLC experiment? (not the range that might be desired or useful for some analytical purpose, but the absolute limits)

6. Consider the structure of ferrocene (you may wish to refer to the "Ferrocene 3D Models" item on our Blackboard site). a. Focusing solely on the hydrocarbon parts (bonds within one ring or the other, completely ignoring the iron atom and all bonds to it), what is the apparent geometry and hybrization of those carbon atoms? b. To how many carbon atoms is the iron atom actually covalently bonded?

7. (2 pts) Draw the structure of chloroethane; any style is okay as long as the carbon–carbon bond is explicitly visible. Draw a line through this C–C bond (you may wish to use a different color), and then consider the two parts (“fragments” of the whole molecule) you would have if this bond were to break. Calculate the mass of each fragment using the same method as for M+/molecular ion analysis. If a fragment has a halogen atom, also calculate the mass of that fragment using the other common isotope of the halogen.

8. Calculate the empirical formula of a chemical whose elemental analysis is: %C: 40.67 %H: 8.53 %N: 23.71 %O: 27.09

Answer 1

5. What is the full numerical range of possible Rf values in a TLC experiment? (not the range that might be desired or useful for some analytical purpose, but the absolute limits)

Typically, we allow the mobile phase to go up to the "Rfinal" mark, or final reference. This is the distance travelled by the solvent (mobile phase). It starts at solvent level, it is R0, therefore.

Rf = distance traveled by sample / distance traveled by solvent

Then, "Rf" value allows us to understand the affinities of anaytes towards the solvent.

Therefore

0 =< Rf =< 1

that is, from 0 to 1 will be a valid vlaue for Rf

6. Consider the structure of ferrocene (you may wish to refer to the "Ferrocene 3D Models" item on our Blackboard site).

a. Focusing solely on the hydrocarbon parts (bonds within one ring or the other, completely ignoring the iron atom and all bonds to it), what is the apparent geometry and hybrization of those carbon atoms?

They appear to be SP2 hybridized, similar to benzene due ot the 120° angle

b. To how many carbon atoms is the iron atom actually covalently bonded?

Only two carbons, one form each side