Things I have learnt from Qs Flashcards
1
Q
What type of molecules have 3 atoms in a row in it + example
A
ones with 6 atoms around the central atom
SF6
2
Q
How do you find the overall charge of a metal complex
A
sum up the charges of individual ions
3
Q
what is a buffer made of?
A
weak acid and ITS conjugate base
4
Q
What state are the elements in in enthalpy of formation AND how many moles are produced?
+1 more thing to remember
A
-standard
-1 mole
-diatomics
5
Q
Why does ethoxyethane (an ether) exhibit H bonding when mixed with water?
A
due to similar shape to water
6
Q
If an (amine) has a longer chain, what does this mean for volatility and solubility
A
both decrease
7
Q
haloalkane+alkoxide->
A
ether
8
Q
what is condensation?
A
when 2 molecules join together and a small molecule (e.g.water or H) is removed from where they join
9
Q
For markovnikov, which atom of a monohaloalkane joins to the C with more H?
A
HYDROGEN
10
Q
haloalkane+e.g. ethanolic potassium cyanide
A
->nitrile->hydrolysed with dilute acid->carboxylic acid
11
Q
how can you tell reduction has taken place
A
+H (less O in ratio)
12
Q
Why can benzene not take part in addition reactions? e.g. with Br
A
no C=C double bond
13
Q
In Sn1, how many molecules are in the rate determining step?
+what if a molecule is 0 order
A
1
0 order has no impact
14
Q
What if a substance readily absorbs H2O?
A
It has a changing mass so is unsuitable as a primary standard
15
Q
Should primary standards be soluble or insoluble in H2O
A
soluble
16
Q
When asked to ‘calcule temp when reaction is just feasable’, do you need <>
A
no
17
Q
What if the energy gap between d orbital subsets is small for metal complexes
A
electrons can be promoted more easily as less energy is required (longer wavelengths absorbed ->e.g.red)
18
Q
When electrons are promoted, what can this make?
A
unpaired electrons
19
Q
If there is an odd number of electrons in a subshell, what does this always mean?
A
There are unpaired electrons
20
Q
What can test for the presence of copper ions?
A
flame test/atomic emission/atomic absorption
21
Q
Describe weighing accurately approximately
A
The sample is weighed out as close as possible to the desired value but the EXACT value is KNOWN (not recorded)
22
Q
rate equation
A
rate=k[][]
23
Q
k rate constant units remembering statement
A
lovely mini skunk
24
Q
What happens when an equilibrium reaction in which 2 enantiomers are formed (enantiomers in equilibrium with each other) is left for a while
A
optical activity decreases as racemic mixture forms
25
If there is an arrow with a substance above or below it in an equation, what is it?
a catalyst
26
what acts as a catalyst in the fries arrangement?
AlCl3
27
What is required for the initiation step of Br2 in a free radical chain reaction mechanism for the substitution of a Br atom?
UV light
28
What must be included in a heating by reflux diagram?
-be cross sectional with inner wall mechanism
-be an open sustem
-be sealed around the flask neck
-water in at bottom and out at top
29
How can the products of hydrolysing an ester be described and what happens to the layers when all the ester is hydrolysed?
-soluble as they both contain polar groups
-there is only a water soluble layer left
30
why is the solution of the salt sodium 4-hydroxybenzoate pH>7
1-4-hydroxybenzoate ion removes H+ by joining together to form molecules of 4-hydroxybenzoic acid
2-H2O equilibrium shifts to right to replace H+ ions and this increases the OH- ions making pH>7
31
What happens to molecule properties when there is a lack of H bonding?
molecules are further apart so the bp is lower
lower solubility in water
32
how would you name
—>—O—
2-methoxy-2-methylpropane
33
What MUST you show in the sn1 mechanism?
show that the - charge is going to the carbocation with arrow
34
What is an alkoxide?
the H in -OH is substituted for a metal
35
what id a nitrile group?
-C triple bond N
36
where can you find ionic radii
data book
37
INDICATOR REMINDER
DONT GET MIXED UP BETWEEN NAMES
38
what does exothermic mean?
a decrease in enthalpy of the SYSTEM
39
Is 🔺S + or - for exo reactions?
-
40
Is 🔺G + or - for exothermic reactions?
-
41
How many pi bonds to sp2 and sp3 bonds have
sp2->1
sp3->0 only sigma
42
What must you remember when counting sigma bonds
Hs
43
Are the bonds in benzene equal or unequal length?
equal
44
what is a planar molecule?
flat
45
What do drugs bind to?
the receptor
46
what reagent is used for -CN -> -COOH
Dilute HCl (aq)
47
what is emission spectra?
a series of lines at discrete wavelength that correspond to different electron transitions
48
FIRST WORD STARTS WITH S AND THE SECOND STARTS WITH F. WHAT IS IT????
SIGNIFICANT FIGURES
49
Towards what side does K increase
product
50
what do these mean in molexules
-dashed line
-wedged line
-into page
-out of page
51
what dies a double bond mean for repulsion
electron rich so more repulsion
52
are charge and oxidation normally the same
yes
53
what order do reactants that don’t take part in the rate determining step
0
54
what units are used in ppm
mL and L
mg and L
55
dative covalent bond
both electrons are from the same atom
56
bond description for geometric isomers
restricted rotation or lack of FREE rotation
57
are the number of moles the same in diluted nad undiluted?
yes
58
breaking C=C steps
1-addition of HBR
2-substitution
59
shape of 1 d orbital
4 leaf clover (holds 2 electrons)
60
Acid-donate or accept H
DONATES
61
what acid does -chloride come from?
hydrochloric
62
what is ammonia?
a weak base
63
What happens in reaction if P is 1st order and Q is 2nd order?
2 particles of P react with 1 of Q in rate determining step. 2nd Particle of P must react in another step
64
What always happens as concentration decreases
ROR decreases
65
what happens to ROR when 1st order reactants are doubled?
Doubles
66
C-H hybridisation (if C forms 4 single bonds) and C triple bond c hybridisation
sp3
ONLY sp hybridisation
67
hydrolysis
adding H20 at break to make 2 molecules from 1
68
what is the filtrate?
the substance passed through the filter
69
How would you find n in Na2CO3•nH2O
find masses of Na2CO3 and H2O
convert into moles to get ratio
70
What to say instead of unfilled d orbitals
INCOMPLETE
71
what shoudl yoy remember to do when using 🔺S in equation
CONVERT
72
Feature that allows for coloured compounds
conjugated system
73
diagram for TLC
beaker
paper
solvent below line
line
2 spots (pure and extract)
74
In distillation, in what circumstance can pure substance not be extracted
if boiling points are similar
75
how manh peaks does H in hydroxyl have in H NMR
1
76
what does ‘reaction is first order with respect to both reactants’ mean
each reactant is order 1
overall reaction=order 2
77
what to use instead of ‘made’
prepared
78
how to make a calibration graph
1standard solutions prepared
2a suitable filter
3-mention of blank/solvent only measurement
4-absorbance of each is plotted
79
what to write instead of propanol
propan-1ol
80
how would you test no more ions remain in solution
add more of a reactant and no more precipitate should form
81
what is the precipitate?
the insoluble solid product
82
% by mass qs
1-Find % of (GFM of ion/element)/(GFM of precipitate) x 100
2-Use % to find mass in precipitate
3-May need to change into moles if there is a mole ration OR concentration change
4-use % mass formula with element/ ion and og sample
83
what must you do with the volume required to make a solution of potassium sulfate K2SO4 if finding potassium soncentration
half it since there are 2 particles for every sulfate
84
Name an unsuitable primary standard
NaOH
85
What could be used to dilute by a factor of 10
25cm3 pipette and 250cm3 standard flask
86
If finding oxidation number of Cr2 what must you do
divide by 2
87
What does the equation look like in gravimetric analysis and why?
Na2CO3•10H2O
heating will release 10 H2O molecules so that only NA2CO3 remains
88
how many steps is hydrolysis
1
89
how many steps is the addition to an alkene
2
90
If moles of X2Y is 1, what is the moles if X
2
91
what do you need to remember when drawing skeletal formula of ethers
write in O
92
how are the orbitals Chromium and copper filled?
an electron borrowed from 4s
93
If given the 🔺G for several reactions, how do you work out the 🔺G for another reaction
Add together the free energies of turning the reactants of this other reaction into their products (flip any that are the other way around)
94
What state is Br2 at room temp?
liquid
95
elements that are:
-liquids
-gases
-solids
-mercury and bromine
-all the noble gases
-O2, N2, H2, Cl2, F2
-the rest are solids
96
What graph could be produced for a 0 order reactant X
-[X] against time
-indirectly proportional
-concentration of X would decrease as time increases since X is used up as the reaction proceeds
-rate against [X]
-straight line
97
What graph could be produced for a
1st order reactant X
-[X] against time
-decaying exponential curve
-rate against [X]
-directly proportional straight line
98
What graph could be produced for a 2nd order reactant X
-[X] against time
-curvier decaying exponential curve
-rate against [X]
-Increasing exponential curve
99
What sort of reaction is involves homolytic fission?
alkane->monohaloalkane
This is free radical chain reaction substitution. Radicals in initiation step are formed by homolytic fission
100
What reactions involve heterolytic fission
-nucleophilic and electrophilic substitution
-electrophilic addition
101
What type of amines have a lower melting point
tertiary because of lack of H bonding
102
What must you say when describing how colour is produced in elements
when electrons fall down to LOWER ENERGY LEVELS
103
How is ammonia written in complexes?
amMine
104
Techniques used to determine concentration of ions in compound
-colorimetry
-atomic emission/absorption spectroscopy
-precipitation
105
How to tell if sn1 or sn2 will occur
If carbon is primary, sn2 will most likely occur
106
how would you write the molecular formula for a carboxylic acid and its ion
CH3COOH
CH3COO-
107
Watch out for equilibrium calculation questions and, also, what should you watch out for?
concentrations can be used if it’s in a 1litre container
108
what type of reaction is dehydration?
elimination
109
What is electrophile in HBr?
H
110
describing why a salt solution is alkaline
The ion from the salt reacts with H+ from the water
The water equilibrium shifts to the right
111
what sample is used in mixed melting point analysis
only a mix of sample and pure
112
What do heterogeneous catalysts adsorb?
reactive molecules onto their active sites
113
What is true for neutral solutions ONLY at 298K (25degreesC)?
-pH=7
-Ionic product Kw=1.01x10^-14
-[H3O+]=1x10^-7
114
What is true for neutral solutions at ANY temperature?
[H3O+]=[OH-]
115
does pressure affect K?
NO
116
is the order of a reaction dependent on the stoichiometry of the overall reaction?
NO (only reactants)
117
What may cause ionisation energy to be higher
Stability due to half full SUBSHELL
118
definition of weak acid/weak base
partially dissociated into ions IN AQUEOUS SOLUTION
119
what id 1l of solution equal to?
1000g
120
why does adding H ions to the salt of a weak acid result in the formation of undissociated weak acid molecules?
H ions react with the conjugate base
121
why do different bonds absorb different wave numbers of infrared radiation
different atoms in bond/different types of vibration
122
name the types of splitting of peaks in H NMR
singlet
doublet
triplet
quartet
quintet
123
124
how many proton environments in a phenyl
3
125
is C=O part of the chromophore?
YES
126
how to draw nucleophilic attack step
one curly full arrow from hydroxyl O to carbonyl C
127
how may different chemicals bind to the same receptor?
similar shape/the same structural fragment
128
what shapes of molecules can only be made if there are lone pair/s of electrons?
trigonal puramidal
angular
129
can heterogeneous and homogeneous catalysts change oxidation states?
Yes
130
are these exo or endo?
1-burning into gas
2-evaporation into gas
3-conversion to solid
1-exo
2-endo (think of a puddle)
3-exo (think of freezing)
131
132
Difference between molecules in rate determining step and not in rate determining step
and link to rate equation
The power in rate equations show how many of these molecules are in the rate determining step.
If there are molecules in the overall equation that don’t appear in this then they must react with the intermediate in another step
133
why are the molecular orbitals in alkanes symmetrical?
The bond is non-polar covalent
134
Is it s quantum number or ms?
ms
135
In gravimetric analysis, why may the percentage by mass be lower than expected
not all acid extracted out
not gone to completion
not enough reactant added
transfer loss
136
water’s role in dissociation of acid
base
proton accetor
137
what sort of solution must the acid be in a back titration
known quantity and concentration
