Lab 3: Fractional Distilltion

Question 1

Theoretical plates

Answer 1

More than distillation due to dashing rings which increases the surface area inside the column. Increasing theoretical plates.

Question 2

Temperature gradient

Answer 2

Lower temperature at top (boiling point of component currently distilling) higher temperature at the bottom (BP mixture in stillpot)

Many vaporization/condensation cycles happen in column

Vapor phases more more concentrated in more volatile component since more volatile has higher partial pressure and since miles increases with each

Question 3

Factors effecting theoretical plates

Answer 3

1. Temperature gradient
2. Surface area. Increases so does plates
3. Column length increase length increase plates
4. Rate of gas flow (GC ONLY)

Question 4

HETP formula

Answer 4

Column height / theoretical plates

Question 5

HETP

Answer 5

1. Measure of efficiency of a fractionating column or GC

2. Lower HETP less height needed for 1 N more efficient column

Question 6

Fractional distillation

Answer 6

Separate a compound from a nonvolatile one by simple distillation. If their boiling points differ by at least 40-50.

Question 7

Composition of the vapor equilibrium with the solution when it first starts to boil

Answer 7

Determined by drawing horizontal line from the liquid line to the vapor line.

Which means that the vapor phase is richer in the more volatile component. Than is the boiling liquid with the which the vapor is in equilibrium.