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Essential Chemistry BS4101 (T1) year 1 - undergrad flashcards > Essential Chemistry > Flashcards

Essential Chemistry Flashcards

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1
Q

Give e.gs of H-bonds found in bio- systems

A
  • base pairs in DNA
  • alpha helix proteins
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2
Q

equation for volume-volume percent concentration? (% v/v)

A

%v/v= ( volume of solute(mL)/ volume of solute(mL)+volume of solvent(mL) ) x100

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3
Q

What is the equation for: Kb, association constant for weak bases?

A
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4
Q

what is the value of:

  1. pico
  2. femto
A
  1. pico = 10-12 m
  2. femto = 10-15 m
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5
Q

define secondary (20) standard

A
  • prep. in lab for spec. analysis
  • standardised against a 10 standard.
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6
Q

Define precision

A

the proximity of several measurements to: each other

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7
Q

Define: Amphiprotic molecule, giv an e.g

A

a molecule that both donates H+ (acid) and accepts H+(base)

e.g water

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8
Q

equation for mass-volume percent concentration? (% m/v)

A

%m/v = ( mass of solute (g) / volume of solvent (mL) ) x100

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9
Q

Give 3 examples of properties of

  1. chemical
  2. physical
A
  1. .b.p, density, m, v i.e. the whole of; density=m/v
  2. flammability, corrosiveness(i.e.rusting), reactivity w/H+ (acid),H2O, O2
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10
Q

what are the properries of 10 standards? (7 marks)

A
  1. v. pure
  2. stable
  3. no H2O’s of hydration
  4. high molecular weight
  5. low hygroscopicity (to min. weight changes due to humidity)
  6. high eq. weight (min. weighing errors)
  7. non-toxicity
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11
Q

what is the general rule between the strength of an acid and its conjug. base?

A

The stronger the Ac, the weaker the Conj. Base (vise versa)

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12
Q

equation for percentage concentration (mass/mass)

A

% mass/mass = ( mass of solute(g) / mass of solute(g) +mass of solvent(g) ) x100

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13
Q

define heterogeneous mixture? (opp for Homogeneous)

A

mixture with diff. composition, properties and appearance e.g salad with lettuce and cucumbers

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14
Q

What is MIC? (Minimum Inhibitory Concentration)

A

MIC: the lowest concentration of an antimicrobial that will inhibit the growth of an oragnism

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15
Q

define: combination reaction

A

2 or more subs react to form 1 product

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16
Q

which measuring equipment has the highest level of accuracy?

A

vol. flask

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17
Q

What is the rule for:

  1. pKa in acids and
  2. pKb in bases
A
  1. Smaller pKa = ^er Ka => ^er acid (smaller pH)
  2. Smaller pKb = ^er Kb => ^er base (bigger pH)
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18
Q
  • Define weak electrolytes,
  • give e.gs
A
  • partially dissociates when dissolved in water.
  • e.gs: PARTIALLY SOLUBLE IONIC SALTS, weak acids, weak bases.
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19
Q

what is the rule for pH, H+ ions and acidity

A

lower pH = higher no. H+ = more acidic

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20
Q

equation relating to pKw, pH and pOH?

A

pKw = pH + pOH = 14

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21
Q

what are the values of pico and femto?

A

pico = 1 x10^-12 m, femto = 1 x10^-15 m

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22
Q

Define strong electrolytes and give e.gs

A

compl. dissocates in water.
e. gs: SOLUBLE IONIC SALTS, strong acids, strong bases

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23
Q

give 2 e.g equations for strong electrolytes

A

acid: HCl → H+ + Cl-
base: NaOH → Na+ + OH-

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24
Q

give an e.g of a weak acid

A

Carbonic acid, H2CO3

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25
Q

equation for pOH?

A

pOH = -log[OH]

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26
Q

Define stock solution

A

concentrated solution that’ll be diluted to some lower concentration for actual use

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27
Q

equation for dilution of solution

A

C1 x V1 = C2 x V2

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28
Q

Describe function of:

  1. electrolyte (ionic comp.)
  2. non-electrolyte (non-ionic comp.)
A
  1. electrolyte: dissolves into cations and ions in a polar solvent e.g H20
  2. non-electrolyte: does not form ions when in solution. e.g glucose
29
Q

name the 5 SI units, their physical quality and abbreviation

A
30
Q

what is the gen. acid-base pair equation and give a gen. e.g

A
31
Q

Give 3 e.gs of non-ionic but polar compounds.

A

sugar, proteins, DNA all dissolve in water.

32
Q

3 possible units for molarity?

A

M, mol/L or molL-1

33
Q

Define: Amphoteric , give an e.g

A

acts as both a base and an acid.

34
Q

define: solution

A

homogeneous mix of 2 or more pure subs.

35
Q

Define accuracy

A

the proximity of a measurement to: the true value of a quantity

36
Q

define: intramolecular H-bond

deine: intermolecular H-bond

A
  • H-bond w/in molecule. (e.g. protein tertiary structure)
  • H-bond between molecules. (e.g. DNA double helix)
37
Q

describe: doubling dilutions (3marks)

A
  • Good for accurate coverage of a narrow scale.
  • Used in many serological assays
  • 2-fold descrease of conc. 400 micrograms per ml → 200, →100 and so on.
38
Q
A
39
Q

equation for molarity?

A

M= n/v, Molarity(M)= Moles(mol) / Volume (Litres, L)

40
Q

define

  1. Mobile phase
A

The liquid or gas that flows through a chromatography system, moving the materials to be separated at different rates over the stationary phase

41
Q

define stationary phase

A

Matrix (solid or liquid): examples include the silica layer in thin layer chromatography TLC

42
Q

give the general formula for alkanes, alkenes and alkynes

A

alkane = CnH2n+2

alkene = CnH2n

alkyne = CnH2n-2

43
Q

how do i know which substance is most polar on a TLC plate

A

most polar, the one that stayed closest to the bottom (the one that moved the least)

expl: mobile phase - non-polar and travels to top, thus, if one doesn’t travel that much, it is less non-polar and therefore, more polar because like attracts like, so the non-polar substance will move with the non-polar mobile phase.

44
Q

state if the following are polar or non-polar

  • mobile phase
  • stationary phase
A
  • mobile phase = non-polar
  • stationary phase = polar
45
Q

define chromatography

A

Physical method of separation that distributes components to separate between two phases, one stationary (stationary phase), the other (the mobile phase) moving in a definite direction.

46
Q

define retardation factor, Rf

A

Distance migrated by sample on a TLC plate under set conditions

47
Q

define retention time, Rt

A

Characteristic time it takes for a particular analyte to pass through the system (from the column inlet to the detector) under set conditions

48
Q

define : normal phase

A

The stationary phase is polar and the mobile phase is relatively non-polar. Order of elution: least polar first, most polar last

49
Q

define reverse phase

A

The stationary phase is non-polar and the mobile phase relatively polar.

50
Q

define: eluate

A

Mobile phase leaving the column.

51
Q

define: eluent

A

Mobile phase leaving the column.

52
Q

what do all macromolecules contain

A

asymmetrical carbon AKA chiral centre

53
Q

what does it mean if all macromolecules containn a chiral centre .

A

they show stereoisomerim

54
Q

define stereoisomerim in macromolecules

A

molecules that show the same structure but different biological properties

55
Q

give 3 types of biological macromolecules and examples following them and wehat they are made of

A
  1. proteins - e.g enzymes, receptors, - aas
  2. DNA - N/A - nucelic acids
  3. carbs - N/A - sugar
56
Q

explain the chirality and biological significance

A

carbon atoms are attached to same groups thus, they have sae molecular weight as eachother but differ in 3D spacial arrangements of atoms

57
Q

what does it mean if spacial arrangement is different?

A

diff spacial arrangement leads to failure of binding to a certain receptor active site

58
Q

explain relationship with chirality in drug molecule

A

chirality in drug molecule creates different enantiomers, thus only one can bind to receptor active site. this is due to spacial arrangement of functional groups being diff.

59
Q

explain the 4 points of configuration isomers that differ to confirmation

A
    1. 3D spacial arrangement of atoms or groups w/in a molecule.
  2. changing the config of mol. means that bonds are broken or reformed
  3. diff configs means diff molecules
  4. High E process
60
Q

Define and describe Conformation & Torsional angle (3marks)

A
  1. Rotatation of single bonds
  2. Low Energy Process
  3. 3600 confirmations
61
Q

describe the diff. btwn bond vs torsional angle

A
  • bond angle: angle btwn 3 atoms
  • torsional angle - angle btwn 4 atoms
62
Q
A
63
Q

what does total number of confirmations depend on?

A

it depends on number of rotatable bonds and torsional angle

64
Q

give equation relating to total no of confirmations

A

Total no of confirmations = (360/T)R

T - tosional angle

R - number of rotatable bonds i.e. <u><em>C-C or C-N</em></u>

65
Q

describe the trend if the no of rotational bonds increase?

A

increase of no of rotational bonds = higher value = increase of total no of confirmations = lower chance for molecules to bind to active site of receptor

66
Q

what happens if there are less confirmations

A

the less confirmations = more effective the drug = more active site binding

67
Q

what can confirmational restriction lead to

A

higher activity

68
Q

what happens if confirmational restriction increases

A

loss of compound activity, thus active confirmations no longer form

Essential Chemistry BS4101 (T1) year 1 - undergrad flashcards (1 decks)

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