Yr 12 content Flashcards
(167 cards)
1
Q
What are isotopes?
A
Atoms of an element with different number of neutrons (same number of protons)
2
Q
What is relative isotopic mass?
A
Mass of an isotope compared to 1/12th of an atom of C-12
3
Q
What is relative atomic mass?
A
Weighted mean mass of an atom of an element compared to 1/12th of an atom of C-12
4
Q
When is relative molecular mass used and relative formula mass used?
A
Molecular for simple molecular, RFM for giant lattices
5
Q
What is the formula of the nitrate ion?
A
NO3 -
6
Q
What is the formula of the carbonate ion?
A
CO3 2-
7
Q
What is the formula of the ammonium ion?
A
NH4 +
7
Q
What is the formula of the sulfate ion?
A
SO4 2+
8
Q
What is the formula of the zinc ion?
A
Zn2+
9
Q
What is the formula of the silver ion?
A
Ag+
10
Q
What is the meaning of Avogadro’s constant and its figure
A
6.02 x10^23, number of particles in a mole
11
Q
What are the units for molar mass?
A
g/mole
12
Q
What are the units for the molar gas volume?
A
dm3 / mole
13
Q
What is the difference between empirical and molecular formulae?
A
EF = simplest ratio, MF = actual number of atoms
14
Q
What is the difference between hydrated and anhydrous?
A
Hydrated contains waters OF CRYSTALLISATION
15
Q
What is meant by the dot in a dot formulae?
A
It tells you how many waters of crystallisation in the structure
16
Q
What is the ideal gas equation?
A
pV = nRT
17
Q
What are the units for each quantity in the ideal gas equation?
A
p = Pascals, V = m3, n = moles, R = constant (data sheet, 8.314), T = K (add 273 to C)
18
Q
What is the formula for percentage yield?
A
(Actual moles of product / theoretical moles ) x100 (can also be done with mass)
19
Q
What is the formula for atom economy?
A
(Mr of desired product / Mr of all products) x100
20
Q
What is the formula for percentage uncertainty?
A
(Error of apparatus / measured value) x100 . If measurement is a change, you need to errorx2 on top.
21
Q
What is the formula of sulfuric acid?
A
H2SO4
22
Q
What is the formula of nitric acid?
A
HNO3
23
Q
What is the formula of ethanoic acid?
A
CH3COOH
24
What is the formula of ammonia?
NH3
25
What is an acid?
Proton donor / released H+ ions
26
What is an alkali?
Proton acceptor / releases OH- ions
27
What is a salt?
Formed when the H+ ION(s) an acid are replaced by metal ION (or other + ion)
28
What is the difference between a strong and weak acid?
Fully/partially disasociating
29
What is the difference between a concentrated and dilute acid?
Amount of moles per unit of volume
30
What is the ionic equation for neutralisation?
H+ + OH- --> H2O
31
What is a base?
Is a substance which neutralises an acid (oxides, carbonate, but alkalis too)
32
What is formed with acid + carbonate
Salt + water
33
What is formed with acid + metal hydroxide
Salt + water
34
What is a standard solution?
A solution of known concentration
35
What are the oxidation numbers of uncombined elements?
0
36
What are the oxidation numbers of combined metals?
Positive but depends on group eg Na is +1, Mg is +2, transition metals can vary
37
What is the oxidation number of each element in NaH?
Na = +1, H = -1 (exception)
38
What is the oxidation number of each element in H2O2?
H = +1, O -1 (exception)
39
When are roman numerals used in systematic names?
To show the oxidation state of elements that can vary
40
What is oxidation in terms of electrons?
Loss of electrons
41
What is oxidation in terms of oxidation number?
Increase in oxidation number
42
How many electrons can fill each of the first 4 shells?
1 = 2electrons, 2 = 8 electrons, 3 = 18 electrons, 4 = 32 (2+8+10+14)
43
What is an orbital?
A region around the nucleus which can hold up to 2 electrons with opposite spins
44
What is the shape of an s orbital?
Sphere
45
What is the shape of a p orbital?
Dumb-bell
46
What is the number of orbitals making up s, p and d sub-shells?
s subshell = 1, p subshell = 3, d subshell = 5
47
What is the number of electrons that can occupy s, p and d sub-shells?
s subshell = 2, p subshell = 6, d subshell = 10
48
Put the first 3 shells and 4s and 4p in order of increasing energy
1s 2s 2p 3s 3p 4s 3d 4p (4s is first in and first out)
49
What is an ionic bond?
Electrostatic attraction between oppositely charged ions
50
For orbitals with the same energy (eg within the 2p sub-shell) describe the order electrons fill
Singly in orbitals within a subshell before pairing up
51
What is an ionic lattice?
Regular structure of positive and negative ions held together by ionic bonds
52
What is a covalent bond?
Strong electrostatic attraction between a shared pair of electrons and the nuclei of bonded atoms
53
What is the relationship between average bond enthalpy and covalent bond strength?
Higher bond enthalpy = stronger covalent bond
54
What is the name of the shape and the bond angle of a molecule with 6 bonded pairs and no lone pairs?
Octahedral, 90
55
What is the name of shape and bond angle of a molecule with 4 bonded pairs, no lone pairs?
Tetrahedral, 109.5
56
What is the name of shape and bond angle of a molecule with 3 bonded pairs, no lone pairs?
Trigonal planar, 120
57
What is the name of shape and bond angle of a molecule with 2 bonded pairs, no lone pairs?
Linear, 180
58
What is the name of shape and bond angle of a molecule with 3 bonded pairs, 1 lone pair?
Pyramidal, 107
59
What is the name of shape and bond angle of a molecule with 2 bonded pairs, 2 lone pairs?
Non-linear, 104.5
60
State why some molecules are polar overall
Assymetrical, dipoles do not cancel
61
State why some molecules are non-polar overall
Symmetrical, dipoles cancel
62
What is electronegativity?
A measure of an atom's ability to attract the electrons in a covalent bond
63
What is a permanent dipole?
A difference in electronegativity of bonding atoms
64
Name the 3 bonds that give rise to hydrogen bonding
OH, NH, FH
65
Name 2 anomoloud properties of water
Relatively high bpt, low density of solids
66
What casues London forces?
Random movement of electrons within orbitals --> temporary dipole --> induced dipole
67
How are elements in the periodic table arranged? (3 things)
- Increasing atomic number
- groups by property
- periods showing repeating trends
68
What is the periodic trend in electron configuration across period 2 and 3?
Fill 2 electrons in s orbitals, then 6 in p orbitals
69
What is first ionisation energy?
Energy to remove one electron from EACH atom in one mole of gaseous atoms
70
What is the general trend in first ionisation energy across period 2 and 3?
Increase (larger NC, smaller AR, same ES, overall higher NA)
71
What is the general trend in first ionisation energy down a group?
Decrease (larger AR, larger ES, outweight larger NC, overall smaller NA)
72
What 3 factors affect trends in ionisation energy?
- Nuclear charge
- atomic radius
- electron shielding
- These combine to give nuclear attraction
73
What is metallic bonding?
Electrostatic attraction between + metal ions and - delocalised electrons
74
What is the general structure of giant covalent lattices?
Network of atoms bonded by strong covalent bonds
75
What is the trend in mpt and bpt across period 2 and 3?
Increases with increasing metal ion charge, peaks in group 4 with giant covalent, low for simple covalent structures
76
What happens to the electron arrangement when group 2 elements react?
lose 2 electrons from s orbital
77
What is formed when group 2 reacts with oxygen?
metal oxide
78
What is formed when group 2 reacts with water?
metal hydroxide and hydrogen
79
What is formed when group 2 reacts with acids?
salt and hydrogen
80
What is the trend in reactivity down group 2?
increase (see same reasoning as increased ionisation energy above)
81
What is formed when CaO dissovles in in water?
Forms Ca2+ and OH- ions, limited solubility though so can form Ca(OH)2 (s) precipitate
82
What is Ca(OH)2 used for?
Neutralising acidic soils
83
What is Mg(OH)2 and CaCO3 used for?
Antacids, curing indigestion
84
What is the trend in bpt of the halogens?
Increases down the group (more electrons so stronger London forces)
85
What happens to the electron arrangement when group 7 elements react?
Gain an electron in p subshell
86
What is the trend in reactivity down group 7?
Decreases down the group (larger AR, larger ES, outweigh larger NC, overall less NA and harder to gain electron)
87
What is disproportionation?
Same element oxidised and reduced in a reaction
88
What is formed with Cl2 + H2O
HClO and HCl
Cl2 + H2O ---> HClO + HCl
** learn this equation**
89
What is formed with Cl2 and NaOH
NaClO and NaCl and H2O (equation balanced with 2NaOH)
Cl2 + 2NaOH ---> NaClO + NaCl + H2O
** learn this equation**
90
What is the benefits of chlorine use in water treatment?
Kills bacteria
91
What are the risks of chlorine use in water treatment?
Toxic in high concentrations
92
What are the products of AgNO3 added to Cl-, Br- and I-?
AgCl, AgBr, AgI (precipitates)
93
What are the appearances of the products of AgNO3 added to Cl-, Br- and I-?
White - Cl, cream - Br, yellow - I preciptates/solids
94
What is the use of ammonia in the test for halogen ions?
AgCl dissolves in dilute, AgBr dissolves in concentrated, AgI doesn't dissolve
95
What is the chemical test for carbonate ions?
add dilute nitric acid if bubbles are observed bubble through limewater, if limewater turns clowdy (as a result of CO2) carbonate ions are present.
CO3 2- + 2H+ --> CO2 + H2O
96
What is the chemical test for sulfate ions?
Add (aq) Barium Chloride/Nitrate if a white precipitate forms sulfate ions are present
97
What is the chemical test for halide ions?
Add (aq) silver nitrate to solution if precipitate forms the solution contains halide ions
98
Why must tests be carried out in the order of carbonate, sulfate, halide?
To avoid false positives eg of Ag2CO3 which is a white preciptate
99
What is the chemical test for ammonium ions?
Add NaOH, warm, evolves NH3 gas, proven with damp red litmus turning blue
100
What is activation energy?
Minimum energy needed to start a reaction
101
What are standard conditions?
298K, 1atm pressure, 1mol dm-3
102
What is enthalpy change of reaction?
Enthalpy change for a reaction in the molar quantities in the equation
103
What is enthalpy change of formation?
Enthalpy change when one mole of a compound forms from its elements
104
What is enthalpy change of combustion?
Enthalpy change when one mole of a fuel combusts compeltely
105
What is enthalpy change of neutralisation?
Enthalpy change when one mole of water is formed from acid + base
106
What is the formula for finding Q(heat transfere)?
Q = mc delta T
107
What is meant by average bond enthalpy?
Energy required to break of one mole of bonds in gaseous molecules
108
Why do actual bond enthalpies differ from average values?
Eg C-H bond will differ in different organic compounds
109
Why does increased concentration (or pressure) increases rate of reaction?
More particles in same volume = increased frequency of collisions
110
How can rate be found from a graph?
Gradient (y/x or rise over run)
111
What does a catalyst do?
Increases rate of reaction without being used up
112
How does a catalyst speed up a reaction?
Alternative pathway with lower activation energy
113
What is a homogenous catalyst?
Chemicals and catalyst in same state
114
What is a heterogeneous catalyst?
Chemicals in a different state from catalyst (usually solid catalyst, via aDsorption
115
How do catalysts improve sustainability?
Lowering temp needed for reactions, reducing energy demand and CO2 production
116
What is dynamic equilibrium?
Forward and backward reaction happening at same rate
117
Why doesn't a catalyst change position of equilibrium?
Just speeds up time taken to reach equilibrium
118
What is Kc
Equilibrium constant, [products] / [reactants] (each raised to power of number of moles)
119
What is the relationship between Kc and position of equilibrium?
A higher number, shift is to the right and vice versa
120
What is a homologous series?
Molecules with the same functional group, each successive member differing by CH2
121
What is aliphatic?
Any non-aromatic, Straight chain, branched or cyclic carbon chain
122
What is alicyclic?
A sub category of aliphatic, where carbons make a ring (NOT aromatic)
123
What is the difference between saturated and unsaturated?
Saturated = all single bonds, unsaturated = at least one double bond
124
What are structural isomers?
Same molecular formula, different structural formula
125
What is the difference between homolytic and heterolytic fission?
- Homolytic, each atom gains an electron from the bond.
- Heterolytic, one atom gains both electrons
126
What is a radical?
A species with an unpaired electron
127
What does a curly arrow represent?
The movement of a pair of electrons
128
Why do alkanes have a tetrahedral shape?
4 bonded pairs around C, no lone pairs. Electron pairs repel equally.
129
Describe the bonding in alkanes
Single C-C and C-H bonds, sigma bonds direct end-end overlap, free rotation around sigma bonds
130
What two factors affect Bp in alkanes?
Length of chain (surface points of contact), branching. Explain using London forces.
131
Why do alkanes have low reactivity?
High bond enthalpy, low polarity of sigma bonds
132
Name the mechanism steps for radical substitution
Initiation, propagation, termination
133
What are the limitations of radical substitution?
- Formation of a mixture of products
- further substitutions
- substitutions at different points along the chain
134
Describe the bonding in alkenes
- Pi bonds and a sigma bond
- Restricted rotation around the C=C bond
135
Why do alkenes have a trigonal planar shape?
3 bonding regions, equal repulsion
136
What is stereoisomerism?
Same structural formula, different arrangement of atoms in space
137
What two things are necessary for EZ isomerism?
C=C bond has restricted rotation, each C atom in the C=C bond is bonded to 2 different groups
138
How is cis trans a specific example of EZ isomerism?
One group bonded to each C atom in the C=C bond is the same
139
What is used to determine priority groups in CIP rules?
Atomic number
140
Why are alkenes reactive?
Low bond enthalpy of pi bond
141
What is an electrophile?
Electron pair acceptor
142
What is used to explain major product via Markownikoff's rule?
Stability of carbocation, tertiary > secondary > primary
143
Give three benefits for sustainability for processing waste polymers
- Combustion FOR ENERGY
- organic feedstock
- removal of toxic waste products
144
Why are alcohols polar?
Oxygen is more electronegative than H and C so permanent dipole. Assymmetrical, dipoles don't cancel
145
Why are alcohols soluble in water?
contain OH bonds, so can form hydrogen bonds with water
146
What is the difference between pirmary secondary and tertiary alcohol structures?
Primary, OH bonded to C bonded to one other C....Tertiary, OH bonded to a C bonded to 3 carbons
147
What is the difference between primary secondary and tertiary alcohols in terms of their reactions?
Primary oxidise to aldehydes or carboxylic acids, Secondary oxidise to ketones, tertiary don't oxidise
148
Why would you react halo alkanes with AgNO3 aq?
To test the rate of hydrolysis (forms AgX ppt when the C-X bond is broken)
149
What is a nucleophile?
An electron pair donator
150
What is the trend in rate of hydrolysis of C-X bonds C-Cl, C-Br, C-I?
C-Cl is the strongest so slowest rate, C-I is weakest so fastest rate
151
What are the initiation and propagration steps when CF2Cl2 is turned into radicals in the upper atmosphere?
init - CF2Cl2 --> CF2Cl + Cl.
prop - Cl. + O3 --> ClO. + O2
prop - ClO. + O --> Cl. + O2
152
Briefly describe the difference in experiment set up for reflux and distillation
Reflux is a vertical condenser and it goes back into flask, distillation is diagonal and collects product
153
What is a separating funnel used for?
Removing an organic layer from an aqueous layer
154
Name 2 anhydrous salts used for drying an organic liquid
MgSO4, CaCl2,
155
After separating and drying, what is the final step for preparing an organic liquid?
Redistillation
156
what does IR radiation cause covalent bonds to do?
Vibrate and asborb energy
157
Name 3 covalent bonds that cause global warming
C=O, C-H and O-H
158
In IR Spec, what bond(s) identify an alcohol?
OH
159
In IR Spec, what bond(s) identify an aldehyde or ketone
C=O
160
In IR Spec, what bond(s) identify a carboxylic acid?
OH and C=O
161
Name 2 common uses of IR spec
Monitor air pollution, breathalysers
162
In mass spec what does the molecular ion peak tell us?
Molecular mass
163
What charge do all fragments have on a mass spectrum?
1+
164
What is formed with acid + metal
Salt and hydrogen - redox not neutralisation
165
what is a Pi bond
sideways overlap of p orbitals above and below bonding C atoms
166
what is a sigma bond
direct end-end overlap of p-orbitals
