Mol Mass by Chromatography

Question 1

Sub title?

Answer 1

Determination of an unknown salt M^+X^-

Question 2

Chromatography has 2 main characteristcs:

Answer 2

1. Mobile phase: contains the mixture to be separated and other agents that aid in separation
2. Stationary phase: has a material that interacts differently with each part of the mixture to lead to separation (colored bands), could even be a sheet of paper

Question 3

How are substances separated?

Answer 3

By london, dipole-dipole, hydrogen bonding, ion-dipole, or ion-ion forces

Question 4

What type of chromatography did we do?

Answer 4

ion-exchange chromatography

Question 5

What is cation exchange?

Answer 5

Separates cations. Cations displace H+ ions in the cation exchange resin(stationary phase) which releases them into solution. Higher charges are bound more tightly and take longer (charge per volume). After all cations are bound, elution must occur. Put a new cation in and they will start displacing the old ones at rates according to their charge/size

Question 6

How do you calculate the molar mass of the salt?

Answer 6

Put them in, gather the liberated h+ ions, titrate with a standard NaOH solution. mole acid=mole base=mole metal cations

Question 7

The resin column should be…

Answer 7

FREE of bubbles.

Question 8

In cation exchange chromatography, what common groups covalantly bond to the resin?

Answer 8

acidic groups, SO3-, COO-

Question 9

What ionically bonds to the resin? (hint ionic bonds can be replaced by a different group)

Answer 9

H+, OH-

Question 10

Cations displace….

Answer 10

H+ bound to the resin

Question 11

They come off the polymer according to

Answer 11

charge per unit volume

Question 12

What is elution?

Answer 12

After the cations are bound, you add more cations that selectively over time displace the old cations