Random Flashcards
(56 cards)
1
Q
Br in water
A
orange
2
Q
Cl in water
A
pale green
3
Q
I in water
A
brown
4
Q
Cl in cyclohexane
A
pale green
5
Q
Br in cyclohexane
A
orange
6
Q
I in cyclohexane
A
violet
7
Q
Cl2(aq) + H2O(l) –>
A
–> HClO(aq) + HCl(aq)
(disproportionation)
8
Q
Cl2(aq) + 2NaOH(aq) –>
A
–> NaClO(aq) + NaCl(aq) + H2O(l)
9
Q
group 2 + 2H20
A
group 2 (OH)2 + H2
10
Q
group 2 + acid
A
salt + H2
11
Q
reversible ozone reaction
A
O2 + O –> O3
12
Q
propagation steps ( and overall) ozone
A
Cl• + O3 –> ClO• + O2
ClO• + O –> Cl• + O2
NO• + O3 –> NO2• + O2
NO2• + O –> NO• + O2
O3 + O –> O2
13
Q
order of organic acid strengths
A
alcohols - won’t react with weak or strong bases
phenols - will only react with strong bases
carboxylic acids - will react with weak and strong bases
14
Q
strong acids
A
HCl
HBr
HI
HNO3
H2SO4
HClO4
HClO3
15
Q
weak acid
A
HF
16
Q
strong bases
A
LiOH
NaOH
KOH
Sr(OH)2
Ba(OH)2
17
Q
weak bases
A
NaCO3
Al(OH)3 (insoluble)
18
Q
Limitations of using E values to determine whether reactions are feasible (4)
A
- EA might be too high
- E only works under standard conditions
- If []≠1moldm-³ then it will shift equilibrium and change E
- Reactants must be in aqueous solution
19
Q
Nucleophile
A
A species attracted to an area of electron deficiency, where it donates an e- pair to form a covalent bond
20
Q
Electrophile
A
A species attracted to an e- rich area, where it accepts an e- pair to form a covalent bond
21
Q
how do you write a Kp expression if the reaction contains species of different states?
A
only include gaseous species in the Kp expression
22
Q
Free Gibbs equation
A
∆G = ∆H - T∆S
23
Q
when is a reaction feasible?
A
∆G < 0
24
Q
two features of a dynamic equilibrium
A
- rate of forwards reaction = rate of backwards reaction
- [reactants] and [products] remains constant but are constantly interchanging
25
enthalpy equation (using average bond enthalpy)
breaking - making
26
entropy definition
measurement of dispersal of energy and disorder within the chemicals making up the chemical system
27
what does a great entropy mean?
greater entropy means greater dispersal of energy therefore greater the disorder
28
entropy units
JK-¹mol-¹
29
standard entropy definition
entropy of one mole of a substance understanded conditions
30
when does S = 0
when the temperature is 0K
31
what makes ΔS positive and why?
- change of state from a solid to liquid to gas
- particles are more random therefore energy is more spread out
- increase in number of moles of product compared to reactants
- more moles means more particles are spread out
32
how do you calculate entropy change?
ΣS(products) - ΣS(reactants)
take into account the number of moles of each species
33
ways that the use of catalysts help chemical companies to make their processes more sustainable and less harmful to the environment
- different reactions with higher atom economy
- alternative reaction pathway with a lower activation energy lowers the energy demand
- less fossil fuels burnt
34
how can you tell which direction equilibrium is shifting towards using redox equations and a half cell electrode potentials?
- reduction happens at the most positive electrode and oxidation happens at the most negative electrode
- the reaction where oxidation is occurring will shift equilibrium towards the side with the electrons (lost)
- the reaction where reduction is occurring will shift equilibrium towards the side without the electrons (gained)
35
apart from recycling, state two other methods for usefully processing waste polymers. (2 marks)
- combustion for energy production
- organic feedstock for plastic production (or for other organic chemicals)
36
what will happen to the pH if the volume increases?
pH stays the same IF the concentration of acid and salt change proportionately
37
π bond
sideways overlap of p orbitals from two bonded atoms above and below a plane
38
evidence for the delocalised model of benzene
- enthalpy of hydrogenation is LESS exothermic than the Kekulé model suggests
- benzene doesn't decolourise bromine
- identical bond lengths between C-C and C=C bond length
39
write an equation for a group 2 oxide to form a group 2 hydroxide
XO + H2O --> X(OH)2
40
what must you include in enthalpy profiles?
- reactants and products
- one headed arrows
- ΔH
- Ea/Ec
41
enantiomers/optical isomers
stereoisomers that are non-superimposable mirror images of each other
42
stereoisomers
compounds with the same structural formula but with a different arrangement of the atoms in space
43
define cis-trans isomerism
a type of E/Z isomerism in which there are two non-hydrogen groups and two hydrogen atoms around the C=C bond
44
electronegativity
a measure of the attraction of a bonded atom for the pair of electrons in a covalent bond
45
π bond
sideways overlap of two p orbitals with the electron density above and below the plane of the bonding atoms
46
σ bond
overlap of one orbital from each bonding atom consisting of two electrons and with the electron density centered around a line directly between the nuclei of the two atoms
47
nucleophile
species which is attracted to an electron deficient centre or atom where it donates a pair of electrons to form a new covalent bond
48
electrophile
species which is attracted to an electron rich centre or atom where it accepts a pair of electrons to form a new covalent bond
49
conjugate acid
species which donates a proton to form its conjugate base
50
conjugate base
species which accepts a proton to form its conjugate acid
51
what factors affect equilibrium constants?
temperature ONLY
52
how do you write a Kc expression for a heterogeneous equilibrium?
only include aqueous and gaseous species (exclude solids and liquids)
53
how to draw a standard hydrogen half cell
- beaker of 1moldm-³ H+(aq) solution
- gas syringe and delivery tube providing solution with H2(g)
- Pt electrode
- voltmeter
- full circuit
- KNO3(aq) salt bridge
54
2NO + O2 <--> 2NO2
what happens to Kp if pressure increases?
Kp = p(NO2)² / p(NO)²p(O2)
- equilibrium shifts towards the products as there are a fewer moles
- Kp initially decreases as the partial precious all increased and the denominator increases more than the numerator (x²y > z²)
- the numerator increases to restore Kp
55
compare the enthalpy of hydration of fluorine versus chlorine
- fluorine has a more exothermic enthalpy of hydration than chlorine
- F- has a smaller ionic radius than Cl-
- therefore F- has a greater attraction to H2O
56
what should you NOT say when talking about enthalpy
- use "energy change" instead of "enthalpy change"
- do NOT say released or required
