1
Q
what is the cause of polarity?
A
the electronegative bonds
2
Q
physical properties
A
a characteristic of a substance that can be observed/measured without changing the identity of a substance.
ex. MP, BP, viscosity
3
Q
what physical properties can be easily tested in a molecule?
A
- colour
- pH
- MP + BP
- soluabiliy
4
Q
DEF solubility
A
mean they dissolve/mix
solid disolves in liquid
5
Q
DEF miscibility
A
means they dissolve/mix
liquid mixes with liquid
6
Q
solubility in water
A
water is polar + has H-bonding
so a molecule that is polar is soluble in water
forms H-bonds with eachother
7
Q
what substances disolve
A
LIKE dissolves LIKE
polar + polar
non-polar + non-polar
8
Q
what is the turning point where a substance becomes too long and is deemed non-polar and insoluble
A
4 carbons long
9
Q
Bronsted-Lowery def = ACIDS
A
donate hydrogen ions
10
Q
Bronsted-Lowery def = BASE
A
accept hydrogen ions
11
Q
what functional groups acts as an acid/base
A
carboxylic acid –> very acidic
amine —> very basic
amide —> slightly basic
12
Q
how to test is something is acid/base
A
- add indicator (physical test)
- neutralisation (chemical test)
13
Q
what type of reaction can alkenes undergo?
A
ADDITION (bc double bond = unsaturated)
14
Q
what is a bromine/iodine test
A
PURPOSE: to determine if there is a c=c
if there is solution TURNS COLOURLESS bc it undergoes addition reaction
15
Q
why not use flourne or clorine ?
A
Bc they are gases ar SLC
16
Q
DEF: degree of unsaturation
A
The amount of C = C bonds present in a molecule
17
Q
how does degree of unsaturation impact the bromine/iodine test?
A
๐๐ฎ๐ฆ๐๐๐ซ ๐จ๐ ๐ = ๐ ๐๐จ๐ง๐๐ฌ = ๐๐ฆ๐จ๐ฎ๐ง๐ญ ๐จ๐ I2 ๐๐๐๐๐
18
Q
DEF: iodine number
A
The number of grams of iodine that reacts with 100g of a chemical substance
- It is typically used to determine the degree of unsaturation in large molecules such as fats.
19
Q
FORMULA: iodine number
A
iodine number = m(molecule AFTER reaction) - m(molecule BEFORE reaction)
20
Q
what type of reactions can alcohols undergo?
A
- oxidation
- condensation/esterification
21
Q
oxidation test
A
PURPOSE: identify primary & secondary alcohols.
- do this by adding acidified dicromate or permagonate
- REMEMBER: tertiary alcohols CAN NOT undergo oxidation = reaction cannot happen
22
Q
What are the two reactants required to form an ester?
A
- carboxylic acid
- alcohol
23
Q
esterification test:
A
PURPOSE: test for alcohols
- do this by adding carboxylic acid/alcohol (depends on what ur testing for) + catalyst is H2SO4 (l)
- we know reaction occured bc FRUITY SMELL
24
Q
what if i use amide instead of alcohol in esterification test?
A
- using amide instead of alcohol = no reaction as NO SMELL
25
DEF: molecular formula
provides the number of atoms of each element present in a molecule/compound
26
carbonate test
- adding carbonate as a base for an oic acid
OBSERVATION: bubbles
27
DEF: empirical formula
provides the ratio of atoms of each element present in a molecule/compound
AKA: simplified version of the molecular formula
eg. C2H6 => CH3
28
Mass spectrometry PURPOSE
to determine the molar mass of an organic compound
29
ionisation
process where an element/molecule becomes an ion
30
HOW DOES ionisation happen in a MASS SPEC
1) sample is BOMBARDED with electrons
2) this force knocks off an existing electron out of place
thus OVERALL MOLECULE becomes CATION and ionised
31
FRAGMENTATION in mass spec
when bombarded with electrons, molecules can fragment
the electrons can BREAK covalent bonds between ataons
32
WHAT is the first fragment
it is NEUTRAL
- has free radical = represent with a dot where electron is
33
WHAT is the second fragment
becomes positivly charged. thus cation
34
what is deflection
The ions are passed through a perpendicular magnetic field, which causes them to deflect in CURVED path`
35
DEFLECTION: impact of charge
less charge (eg. +1): lesser deflection
more charge (eg. +2): greater deflection
36
DEFLECTION: impact of mass
heavier: lesser deflection
ligher: greater deflections
37
DETECTION mass spec
- The amount of each fragment that reaches the end is detected, and the relative intensity of each fragment is recorded down.
- Only positive charges get detected.
37
mass TO charge ratio (m/Z)
DEF: the ration of mass of ion to its charge
VCE context: this effectivly tells us the molar mass
37
OVERALL deflection depends on
1) molar mass
2) electric charge
combine: mass TO charge ration (m/Z)
37
Base peak
DEF: the peak with GREATEST abundance
37
Molecular ion peak / parent ion peak
DEF: the peak in a mass spectrum with the GREATEST m/Z ration
parent peak: corresponds to the parent molecule
molecular peak: the ion form of the molecule
TYPICALLY the highest peak at the end of mass spec
38
Estimating Identifying Molecules from Mass Spectrum Steps
1) subtract away molar mass of functional group
2) find number of carbons by dividing by 14 (CH2)
3) double check of molar mass is same as provided in graph
39
EG of isotopes common
12 C or 13 C
1H or 2H
40
ISOTOPES
atoms with the same atomic number (i.e., the same number of protons) but a different amount of NEUTRONS, and thus, a different mass number
41
influence of isotoles
resutlts in a very small peak at end. typically after parent/molecular peak
42
Halogen isotopes
35 Cl or 37 Cl
79 Br or 81 Br
43
relative atomic mass ()
(RAM)
DEF: The weighted average of the relative masses of the isotopes of the element.
44
RAM
formula
45
RIM formla + what?
46
diatomic molecules?
made up of EXACTLY two atoms
47
spectrometry DEF
practical application of measuring and analysing apectra
SINGULAR: spectrum
48
spectroscopy DEF
broader term referring to interactions between matter and electromagnetic radiation (light)
SINGULAR: spectra
49
spectrometry/spectroscopy
the entire process
50
spectra/spectrum
the output graphs are obtained
51
Atoms used in NMR
1H & 13C
- this is because they have odd number of nucleons, thus have magnetic properties
- they have a net magnetic spin on their nucleus
52
electronegativity (NMR context)
when attached to a more electronegative atom, carbon is MORE sheilded so it is LESS aligned with the magnetic feild, so MORE elergy is required to flip the nucleus
53
finding HYDROGENT and CARBON enviroments
1) look at current enviroment
2) look for all neighbours
3) look for any duplicates
54
tetramethylsilane (TMS)
used to calibrate
- if u see a peak at 0 = TMR
- IGNORE IT !!!
55
13C Nuclear Magnetic Resonance
two main things to look out for
1) no. of unique carbon enviroments
2) chemical shifts
56
chemical shifts for CNMR
- lower ppm have a lot of overlap
- higher ppm (above 110ppm) are more distinguishable
higher ppm means MORE energy is required to flip the nucleus, meaning that it is atttached to MORE electronegative elements
57
1 H NMR: low resolution
aka: proton NMR
the ratio of areas under each peak indicated the ratio of hydrogens present in the enviroments
58
integration curve
use ruler to measure leght + consider ration between other peak's inegration curves
59
1 H NMR: high resolution
SPLITTING PATTERN
indicates the nnumber of hydrogen atoms in the immediatly adjacent/neighbouring Hydrogen enviroments
60
SPLITTING PATTERN formula
s = n + 1
s= splits
n= neighbours
61
wave number formula:
wavenumber = 1/alpa
62
purpose of IR spectroscopy
to identify functional groups
63
bond stretching
- greater frequency = greater energy
- greater wavenumber = greater energy
64
c to c no of bond impact on wave length
the more the c - c bonds, the greater the wave number
65
datapoint terminology for IR
- absorbance
- absorbtion band
66
describing terminology for IR
- broad/ narrow
- weak/medium/strong
67
FINGERPRINT REGION
wave number: 500 - 1500
- it is uniquely different to each molecule
- IGNORE IT as its hard to decipher
68
alcohol IR
a high heel around 3000
69
carboxylic acid IR
very narrow and strong (long) around 2000-15000
&
broad around 3000
70
aldehydes. esters & keytones IR
bit narrow at medium (lenght) around 3000
&
narrow and strong (lenght) around 2000 - 1500
71
amine
has an N that before 3000
narrow at around 3000
NH deformation before 1500
72
amide
has an N that before 3000
narrow at around 3000
73
what is melting?
temp at which solid turns to liquid
OR
treaches latent heat of fusion, where substance starts to melt
74
MP of impure substance
- will always be lower
- very impure molecule may not overlap the melting point at all
75
MP range of the PURE SUBSTANCES
narrow MP range of roughly < 2 degrees
76
MP range of the SLIGHTLY IMPURE SUBSTANCES
moderate MP range of roughly 2-5 degrees
77
MP range of IMPURE SUBSTANCES
wide MP range of > 5 degrees
78
MP determination of PURE
- even crystal lattice structure
- stronger intermolecular bonds
- overall MP range within 2 degrees
79
MP determination of Impure
- uneven crystal lattice structrue
- weaker intermolecular bonds
- MP range as said
80
compund identification
match MP of substance to MP of literture value
81
Purity analysis
determined by MP range
82
distillation DEF
a process of seperating a liquid mixture by boiling the mixture
83
distillation PROCESS
1) mixture is heated to the target tempereature
2) substance with lower BP will evaporate and the condense in a condenser
3) it will be collected in a recieving flask
84
TARGET TEMP in distillation
the temperature between the two substances boiling point
85
distillate
the substanc that is evaporated and condensed back down in distillation
86
weakness of normal distillation
can only effectily seperate compunds if boiling boint difference is greater than 50 degrees
87
FRACTIONAL distillation
a more effective way to do distillation
can have substances with a lower difference in BP
88
fractionating column
contains glass beads to maximise condesnsation, RESULTING in a temperature gradient
think: hotter at bottom and cools as u go up
89
KEY FEATURE of a fractionating column
substances undergo multiple evaporation and condensation cycles
90
concentration
DEF: the amount of substance presnet per unit of volume
FORMULA: c = n/v
SI units: mol/L or M
91
concentration (mass/volume)
c = m/V
g/L
92
ppm
parts per million
93
ppb
parts per billion
94
during dilution...
- concentration changes
- amount of substance stays the same
95
aliquot
sample
96
retention time
the time taken for compound to travel through chromatogram
aka Rt
97
mobile phase
moves
98
stationary phase
stationary
99
adsorption
verb: adsorb
- process of a substance is attached to a solid material
"" think: as stick onto a solid surface
100
desorbtion
verb: desorb
- release of an adsorbed substance from a solid surface
""think: unstick
101
polar substance
attracted to POLAR
- primarily undergoes dipole-dipole attractions
102
non-polar substance
attracted to NON-POLAR
- primarily undergoes dispersion forces
103
what is seperation in cromatography BASED ON?
polarity!
104
column chromatography
- made up of glass column with beads
STATIONARY phase: beads + glass
MOBILE phase: solvent
105
High pressure liquid chromatography
HPLC
- simplar to column cromatography
- major difference: uses HIGH PRESSURE, making process faster
106
Substance will have the same retention time if itโs run under the:
1) same HPLC colums
2) same conditions!!
107
Factors Which Affect Retention Time: material
MATERIAL of the stationary phase and mobile phase affect how quickly substances will travel through the chromatogram!
108
Factors Which UNIFORMLY Affect Retention Time:
1) lenght of chromotograph
2) viscosity
3) pressire
4) tightness of stationary phase
5) temp
109
Factors Which UNIFORMLY Affect Retention Time: viscosity
water = shorter Rt
honey = longer Rt
110
Factors Which UNIFORMLY Affect Retention Time: tightness of stationary phase
tighly packed VS not
111
Factors Which UNIFORMLY Affect Retention Time: lenght of chromotograph
shorter = shorter Rt
longer = longer Rt
112
Factors Which UNIFORMLY Affect Retention Time:pressure
low pressire= longer Rt
high pressure= shorter Rt
113
Factors Which UNIFORMLY Affect Retention Time: temp
hot = shorter Rt
cold= longer Rt
114
what does the peak area of the graph tell us?
greater Peak area = GREATER concentration of substance
lesser Peak area = LESSER concentration of substance
115
HPLC qulitative analysis
- what is in the sample?
- measured by: Rt
116
HPLC quantitative analysis
- how much of the sample is there?
- measured by: area under graph
117
standard
a substance with precisly known concentration for use in a quantitative analysis
118
HPLC Quantitative Analysis Process
Step #๐: At least four standards passed through the HPLC column individually.
Step #๐: Peak area is measured.
Step #๐: Plot calibration curve.
Step #๐: Use calibration curve to find concentration
119
Volumetric Analysis
quantitative technique that involves reactions in a solution.
Use: Find concentration of an unknown sample!
120
Volumetric analysis calculations
1. Write out the balanced chemical equation (if not already provided).
2. Find the amount (in moles) of the known substance using n=cv
3. Find the amount (in moles) of the unknown substance using STOICH ratios.
4. Find the concentration of unknown substance using c=n/v
121
titrant
known concentration
122
titre
found in: burrete
123
analyte
unknown concentration
124
aliquote
found in: conical flask
125
rinsing of equipment (all)
all must be first rinised with distilled water to get rid of other substances
126
rinsing of equipment (burette + pipette)
rinse with substance it holds
127
rinsing of equipment (conical flask and volumetric flask)
rinse with distilled water
128
Incorrect Rinsing Steps
1. Draw out a scenario.
2. Identify where the unknown substance is.
3. Link to Volume of the titre.
4. Determine whether it is overestimated or underestimated!
129
acid/base property of water
Water is AMPHIPROTIC,
meaning it acts as both an acid and a base
130
what are protiens made up of?
monomers called amino acids
131
amino acid in a neutral enviroment
BECOMES a zwitterion
132
what is a zwitterion
A molecule having separately positively and negatively charged groups.
BUT OVERALL charge is neutral
VCAA only allows one positive and one negative charge in the zwitterion
133
amino acid in an acidic enviroment
there exists a largeconcentration of [H+]
- SO the amino acid acts as a base
134
amino acid in a basic enviroment
there exists a largeconcentration of [OH-]
- SO the amino acid acts as a acid
135
Side chains of amino acids in acid/base enviroments
side chains acts as acid or base
136
Side chains of amino acids as zwitterions
side chains DON NOT as acid or base
137
AMIDES in side chain of amino acids
are weak bases
- DO NOT become protonated in acidic conditions
138
HYDROXYLS (OH) in side chains of amino acids
DO NOT act as acids and will NOT DONATE H+
139
PRIMARY protein structure
a LINEAR chain of amino acids
- held togeather by peptide/amide bonds
140
Primary Structure is determined by:
1. amino acid which comprise the chain
2. order of amino acids
141
SECONDARY protein structure
The primary structure may bind with itself via H-BONDS to form the
secondary structures
142
where does the h-bond occur for secondary protein structure?
btween the amide functional(N-H) groups and the peptide linkage (c=o)
143
TERITARY protein structure
Overall 3D shape caused by folding and coiling of polypeptide chain due to interactions
between side chains of amino acids
144
types of bonding in tertiary structure
- ionic
- H-bonds
- dipole-dipole
- dispersion
- ion-dipole
145
covalent crosslinkage
- aka disulfide bridge
- this happens generally ONLY between CYSTEINE
- R-S-S-R
146
QUATERNARY protein structure
structure is made up of more than one polypeptide chains
- bonds which bind quaternary strucures togeather is SAME AS TERTIARY
147
chirality
DEF: an object cannot be SUPERIMPOSED on its mirror image by any translations or rotations
found by LOOKING for a line of symmetry
148
Superimposable
means that two objects (usually molecules) can be placed on top of each other so that every part matches up perfectly in 3D space.
149
opposite of chirality
archiral
150
Optical Isomer/Chiral Isomer/Enantiome
Isomers which have different spatial arrangements of atoms. The mirror image of the molecule is unable to be superimposed.
151
requirement for optical isomers
MUST contain a chiral centre
152
chiral centre
where 4 different groups are attached
153
notation for enantiomers
R: rectus (right)
S: sinister (left)
154
how can molecules be mirrored
- mirror the whole molecule
- mirror a bond(dashed to wedged)
155
can a molecule wholly and bond flipped
NO as that means its is the same moecule
156
physical properties of enantiomers
the BP, MP and pH are the same for enantiomers
157
chemical properties of enantiomers
enantiomers have the same chemical properties!!
- enantiomers can react with bases and acids via acid base reactions
- they can also react with alcohols to form esters
158
what r the differences between enantiomers
- bind differently to enzymes
- rotate differently in plane - polarised light
159
catalyst
speeds up the rate of reaction by providing an alternative reaction pathway
160
enzymes
DEF: act as biological catalysts which speed up the reate of reaction
- they are a type of proton
161
oranic catalyse (enzymes) vs inorganic catalysts (e.g metals)
organic: specific and sensitive
inorganic: can catalyse may different reactions and operate in many different conditions
162
substrate
reacting molecule
163
active site
specific area of the enzyme that interacts with substrate
164
enzyme activity
yhe amount of substrate that reacts with enzyme in a given time (rate of reaction)
165
features of enzyme and substrate binding
- enzyme and substrate have complementary shapes
- enzyme is specific for the particular substrate
- enzyme WILL NOT bind to another molecule
DURING BINDING: temporary bonds
166
Lock & Key model: step 1
substrate binds with active site of enxyme
167
Lock & Key model: step 2
ENZYME - SUBSTRATE COMPLEX
- substrate fits perfectly into active site like a key in a lock
168
Lock & Key model: step 3
temporary bonds are formed between substrate and active site
169
Lock & Key model: step 4
the glycogynic linkage is broken and H2O is added
170
Lock & Key model: step 5
products are released
enzyme overall is UNALTERED
171
isomers fitting into enzyme
isomers will not be able to bind to active site of enzymes
optical isomers would change 3D arrangement of substrate.
172
biological activity
the effect of a substance on living organisim/tissue
173
what is enzyme activity affected by
pH & temperature
174
denaturation
process which alters the structure of molecular structure of protein or enzyme
175
active site after denaturation
CHANGED SHAPE
176
enzyme function after denaturation
NON - FUNCTIONAL
177
enzyme denaturation
Enzymes operate only within a narrow ๐ฉ๐ range. The pH at which enzyme activity is greatest is known as the enzyme's optimum ๐ฉ๐.
When pH changes, the charges of certain groups on the side groups CHANGE
- Causes the bonds in the tertiary/quaternary structure of protein to be DISTRUPTED
- Causes the enzyme to be DE-NATURED.
denaturation is a PERMINANTE CHANGE
178
sample response for enzyme/proteins denaturing
1. As the enzyme/protein is placed in *insert conditions* that changes charges.
2. The bonds in the tertiary/quaternary structure are disrupted.
3. The enzyme/protein is denatured.
4. This changes the shape/active site of the enzyme/protein, and thus it no longer
*insert function
179
effect of alcohols on enzyme/protein structure
- intermolecular bonds get wakened/distrubted (bc alcohols have H-bonding)
- protein is de-natured
180
dependance on temp
at greater temp
- kinetic energy increased
- intermolecular bonds break/distrupted
- structure of enzyme changes --> denatured
THUS ENZYME WILL NOT WORK
181
Enzyme activity at lower temp
- kinetic energy decreases --> less frequent and more energetic collisions
- intermolecular bonds ARE NOT DISTRUPTED = enzyme does not denature
- only rate of reaction is decreased
THIS LEADS TO LOWER ENZYME ACTIVITY
182
competative enzyme inhibitors DEF
compete with substrate to bind to active site of the enzyme
- if sucessful it blocks the substrate from interacting witht he enzyme
183
competative enzyme inhibitors: RELATIONSHIPS WITH CONCENTRATION
- adding inhibitors decrease the rate of reaction
- increasing substrate concentration INCREASES reaction rate
even with inhibitors, with suficient substrate concentration, the maximum reaction rate can still be used
184
structures and functional groups in medicines
functional groups in specific arrangements provide organic compounds with their unique chemical properties
- a patricular shape will affect theor biological activity with other substances like enzymes
185
solvent extration
PURPOSE: to seperate substances based on polarity
like polarities attract to eachother
186
solvent extration STEPS
1) mixure placed ina seperation funnel
2) immiscible solvent (opposite polarity ) added and two layers created. funnel shaken and layers allowed to settle
3) polar substances --> polar solvent
nonpolar substances ---> non polar solvent
4) tap @ bottom poened and mixture sperated.
5) solute collected via evaporation of solvent or disitilation
187
why two layers form in solvent extraction?
like attracts like polarity
- non-polar solvent float to top instead of mixing bc it is less dense + has weak dispersion forces
188
CHEM
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