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Pharmacy Practice Lab II > Lab 1 > Flashcards

Lab 1 Flashcards

1
Q

what is sorption?

A

consists of TWO processes: absorption and adsorption

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2
Q

define absorption

A

the process in which molecules cross the membrane interface to enter the interior of the cell

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3
Q

true or false

absorption is not a very important physiological process

A

FALSE – it is very important

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4
Q

define adsorption

A

the process by which molecules of a substance attach to the surface of a solid substance

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5
Q

as mentioned, adsorption is the process in which “molecules of a substance” attach to the surface of a “solid substance”

what is the term for the “molecules of a substance”

what is the term for the “solid substance” which these molecules attach to?

A

molecules of the substance = adsorbate
the solid substance the adsorbate sticks to = adsorbent

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6
Q

an adsorbate is a _______, ____ in _____ or ____ which is adsorbed

A

an adsorbate is a LIQUID, solute in solution, or GAS which is ADSORBED

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7
Q

besides adsorbent, what is another term for the solid substance which the adsorbates cling to

A

interface

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8
Q

sorption consists of how many processes?

A

2 – adsorption and absorption

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9
Q

name the types of adsorption

A

2 –

physical adsorption (Physisorption)
chemical adsorption (chemisorption)

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10
Q

Physisorption is a ____ process where the adsorbate is held to the solid surface by _____ forces

A

a PHYSICAL PROCESS

the adsorbate is held to the solid surface by WEAK, van der waals forces

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11
Q

is physical adsorption easy or hard to break?

A

easy to break through changes in temperature and pH

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12
Q

in physical adsorption, the ______ is easily regenerated.

this process of regeneration is called ____

A

adsorbent

process of regeneration is called desorption

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13
Q

at equilibrium, what is happening with physical adsorption?

therefore, the concentration of the _____ remains constant

A

adsorption and desorption occur at a CONSTANT RATE

concentration of the adsorbate remains constant

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14
Q

in which type of adsorption is desorption easier — physical or chemical?

A

easier in physical because the bond between adsorbate and adsorbent is weaker

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15
Q

explain the forces of chemical adsorption

A

adsorbate and adsorbent are held together by a CHEMICAL BOND (ie: ionic or covalent)

it is a CHEMICAL PROCES

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16
Q

true or false

the adsorbate-adsorbent interactions are stronger in physical adsorption than chemical adsorption

A

FALSE – stronger in chemical

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17
Q

there are several ADSORBENTS available for ____, _____, and ____ effects

A

coloring and refining food, and for their pharmacological effects

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18
Q

adsorbents are typically classified into ____ types:

A

3 types:

  1. Hydrophilic and polar-oxygen containing compounds
  2. Non-polar carbon containing compounds
  3. Porous polymer matrix with polar or non-polar functional groups
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19
Q

give an example of an adsorbent that is a hydrophilic, polar oxygen-containing compound

A

silica gel

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20
Q

give an example of an adsorbent that is a non-polar, carbon containing compound

A

activated carbon and graphite

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21
Q

_____ is a common adsorbent used in pharmacy and medicine

A

activated charcoal

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22
Q

explain how activated charcoal works as an adsorbent

A

it is used to treat toxicity from oral drug ingestion

it can adsorb a wide range of adsorbates (drugs and chemicals)

the drug is ADSORBED by the charcoal, and this reduces the systemic ABSORPTION from the GI tract

23
Q

the amount of adsorbate adsorbed varies according to….

A

the QUANTITY and GRADE (particle size, quality) of the adsorbent

24
Q

what is often used to express the effectiveness of the adsorbent for the specific adsorbate?

A

MOLES OF ADSORBATE adsorbed by a GRAM OF ADSORBENT

25
Q

Temperature is ___ proportional to adsorbtion

A

inversely

26
Q

what factors influence adsorption?
name 5

A

temperature
layers
type of adsorption
concentration of adsorbate
quantity of adsorbent

27
Q

what determines the DISTRIBUTION between the adsorbent and liquid phases?

A

the degree of the adsorbent’s affinity for the adsorbate

28
Q

what determines the affinity?

A

the properties of the adsorbate and adsorbent

29
Q

what determines the capacity?

A

the surface area of adsorbent and active sites present on adsorbate

30
Q

the extent of adsorption depends on..

A

affinity, capacity, and equilibrium conditions

31
Q

what is meant by “equilibrium conditions”

A

temperature and concentration of the adsorbate

32
Q

in adsorption studies, the quantity of adsorbate (___) adsorbed by a unit weight (___/____) of adsorbent (__) at equilibrium concentrations (___) is measured, at a constant ______

A

quantity of adsorbate = x
quantity of adsorbate adsorbed by a unit weight of adsorbent (x/m) m = unit weight of adsorbent
at equilibrium concentrations (C) is measured, at a CONSTANT TEMPERATURE

33
Q

The quantity of adsorbate adsorbed by a unit mass of adsorbent (x/m) exhibits a _____ relationship to _____ and is represented by what equation?

A

LINEAR relationship to GAS PRESSURE
represented by y = mx+c

34
Q

x/m=____

A

kC

where C = concentration of a gas measured as gas pressure

35
Q

at low pressure, the extent of adsorption (x/m) varies ___ with the gas pressure
(according to Freundlich)

A

LINEARLY

36
Q

at moderate pressure, the extent of adsorption (x/m) varies ____ to gas pressure
(according to Freundlich)

A

EXPONENTIALLY

37
Q

at high pressure, the extent of adsorption (x/m) is ____ of gas pressure
(according to Freundlich)

A

independent

38
Q

Irving Langmuir proposed that dynamic equilibrium exists between……

A

adsorbed molecules and the free molecules (concentration at equilibrium)

39
Q

according to Langmuir, adsorption is a ____ order reaction, meaning what?

A

second order, meaning it is dependent on both the adsorbent and adsorbate concentration

40
Q

what did langmuir say about the surface of the adsorbent

A

it is uniform and has a FIXED NUMBER of active sites

41
Q

explain what langmuir said about the adsorption process

A

the adsorbate is adsorbed at the surface as a SINGLE MONOLAYER – molecules of adsorbate do NOT deposit on each other.

one adsorbate molecule is adsorbed to ONLY ONE active site

42
Q

according to langmuir, the adsorption is ____ and ____ via ___ forces

A

RANDOM and NONSPECIFIC via WEAK FORCES (van der waals)

43
Q

according to langmuir, do adsorbed molecules interact with each other?

A

NO.
they do not interact with each other OR with other molecules in the system

44
Q

according to langmuir, at equilibrium, the fraction of the active sites occupied by adsorbed molecules fraction of free active sites is __ to ___

how does this value change ?

A

1-theta

this value remains CONSTANT with specific temperature and concentration

45
Q

the specific area of an adsorbent is…

A

the surface area available on UNIT MASS of adsorbent for adsorption

46
Q

adsorption is useful in treating…..

give a specific example

A

oral drug overdose

alkaloid drugs and theophylline absorption in the GI tract are reduced by oral administration of ACTIVATED CHARCOAL ADSORBENT

the drug is adsorbed to the charcoal and excreted in the feces

47
Q

citric acid is a ___ acid

A

triprotic

48
Q

in this experiment, the concentration of citric acid before and after adsorption to activated charcoal is determined by…..

A

titrating citric acid with a strong base (sodium hydroxide)

49
Q

____ moles of sodium hydroxide neutralize ___ moles of citric acid

explain the rationale

A

3 moles of sodium hydroxide neutralize 1 mole of citric acid.
this is because sodium hydroxide is a monobasic base (has 1 OH-) and citric acid is triprotic, meaning it contains 3 ionizable Hydrogen (3eq/mol)

50
Q

what is the pH indicator used in this experiment

A

phenolpthalein
used to detect the endpoint of neutralization

51
Q

r-squared is a statistical measure of….

A

how close the data are to the fitted regression line

52
Q

in general, the ___ the R-squared, the better the model fits your data

A

higher

53
Q
A

Pharmacy Practice Lab II (12 decks)

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