Key Stuff - Module 3 + 5 Flashcards
(79 cards)
1
Q
1st ionisation energy
A
removal of 1 mole of electrons from 1 mol of gaseous atoms
2
Q
Periodicity
A
Repeating trends in physical + chemical properties
3
Q
Metallic bonding
A
Strong electrostatic attraction bt/w positive ions + delocalised electrons
4
Q
Disproportionation
A
Oxidation + reduction of the same element
5
Q
Activation Energy
A
Minumum energy required for a reaction to take place
6
Q
Enthalpy change of formation
A
Formation of 1 mol of compound froms its elements
7
Q
Enthalpy change of combustion
A
Compete combustion of 1 mol of a substance
8
Q
Enthalpy change of neutralisation
A
Formation of 1 mol of water from neutralisation
9
Q
Average bond enthalpy
A
Breaking of 1 mol of bonds in gaseous molecules
10
Q
Homogenous catalyst
A
Same phase a reactants
11
Q
Heterogeneous catalyst
A
Different phase as reactants
12
Q
Bronsted-Lowry acid
A
Donates a proton
13
Q
Bronsted-Lowry Base
A
Accepts a proton
14
Q
What indicator should you use for strong acid + strong base reaction
A
Phenolphalein or methyl orange
15
Q
Strong acid + weak base
A
Methyl orange
16
Q
Weak acid + strong base
A
Phenolphthalein
17
Q
Weak acid + weak base
A
pH at equivalence - depends on the relative strength of acid + base
18
Q
Lattice enthalpy
A
Formation of 1 mol of ionic lattice from gaseous ions
19
Q
Enthalpy change of solution
A
Dissolving of 1 mol of solute
20
Q
Enthalpy change of hydration
A
Dissolving of 1 mol of gaseous ions in water
21
Q
Entropy
A
Measure of dispersal of energy in a system which is greater, the more disorder a system
22
Q
Standard electrode potential
A
- Electromotive force compared to standard hydrogen electrode
- Standard condition: 298K, 1mol dm-3, 100kPa
23
Q
Units for rate constant (k)
A
24
Q
Rate graphs for 0 order reaction
A
25
Rate graphs for 1st order
26
Rate graphs for 2nd order
27
Rate determining step info
* Slowest step is rate determining step
* Species involved in this step are found in overall rate equation
28
Weak acids
Partially dissociate into ions in aqueous solutions
29
Strong acids
Completely dissociate into ions in aqueous solutions releasing H+ ions
30
Name 3 basic strong acids
- HCl
- HNO3
- H2SO4
31
Name a basic weak acids
Carboxylic acids eg ethanoic acid
32
Name 3 basic strong bases
* NaOH
- KOH
- Ba(OH)2
33
Name a weak base
Ammonia (NH3)
34
State the redox reaction bt/w manganate (VII) + iron (II)
35
Describe the method you would use to do a redox titration calculation
1. Form redox equation
2. FInd the moles of compound
3. Use redox equation to find the moles of unknown
4. Scale up if needed
36
What must you remember when calculating elctrode potential
Reduced electrode potential is always more positive electrode potential
37
Explain the process of a proton exchange fuel cell
1. Hydrogen gas enters system
2. Hydrogen oxidised to H+ at anode
3. Electrons travel via external circuit
4. H+ ions travel through electrolyte + membrane
5. oxygen gas enters cell
6. Oxygen is reduced at cathode
7. Catalyst speeds up reaction bt/w oxygen + H+
8. Water produced
38
Advantages of fuel cells
- Eliminate pollution caused by burning fossil fuels
- Eliminates green house gases if hydrogen used comes from electrolysis of water
- Higher efficiency than diesel or gas engines
39
Alkaline Fuel Cells (AFC)
* Uses alkaline electrolyte eg KOH
- Used by NASA in space shuttles
40
Direct Methanol Fuel Cells (DMFC)
- Uses polymer membrane as electrolyte
- Catalyst on anode draes hydrogen from liquid methanol
- Eliminates need for fuel reformer, pure methanol can be used as fuel
41
Rearranged Arrhenius equation for Ea
Ea = RT (lnA-lnk)
42
Rearranged Arrhenius equation for A
43
Rearranged Arrhenius equation for T
T = Ea / R (lnA-lnk)
44
Ligand
Particle with lone pair thay forms a coordinate (dative covalent) bond to metal
45
Complex
Central metal ion with ligands coordinately bonded to it
46
Coordination number
Number of coordinate bonds from ligand to metal ions
47
Cis-platin
* Anti-cancer drug
* Complex of platinum (II) with X2 chloride ions + X2 ammonia molecules in square planar shape
* Binds to DNA preventing cell division
48
Unidentate ligands
* Donates one electron pair
- Form one coordinate bond
* Eg. [Cu(H2O)6]2+
49
Bidentate ligands
- Donates X2 electron pairs
* Form two coordinate bonds
* Eg. [Cr(NH2CH2CH2NH2)3]3+
50
Multidentate ligands
- Donates several electron pairs
- Form several coordinate bonds
- Eg. [Cu(EDTA)]2-
51
Cr3+
Pale purple
| Looks green in aqueous solutions
52
MnO4 - (OS +7)
Purple
53
Mn2+
Pale pink
54
Fe3+
Yellow
55
Fe2+
Pale green
56
Cu2+
Pale blue
57
Explain what is meant by the term *buffer solution*?
- Buffer solution minimises pH changes
- On the addition of small amounts of acid or alkali
58
How do you reduce Cu2+ & what is the colour change?
- With I-
- pale blue → white ppt but brown solution due I2
59
What transition metal ion spontaneously disproportionates?
- Cu
- 2Cu+ → Cu + Cu2+
- In aqueous conditions
60
What is involved in the interconversion bt/w Fe2+ & Fe3+ & what is the colour change?
- Fe2+ oxidised by (yellow) acidified KMnO4 (aq)
61
What is the standard redox equation bt/w Fe and KMnO4?
62
How do you reduce Fe3+ & what is the colour change?
- With I-
- yellow/brown → pale green
63
What is involved in the interconverstion bt/w Cr3+ & Cr2O7 2- & what is the colour change?
1. Cr3+ (within [Cr(OH)6]3- which is dark green) oxidised to yellow CrO4 2- by warming with H2O2 in alkaline conditions
2. Add H2SO4 to CrO4 2- produces orange dichromate (Cr2O7 2-)
3. (Cr2O7 2-) reduced to Cr3+ (green) by acidified zinc
64
What is electron configuration of Ti?
65
What is the electron configuration of V?
66
What is the electron configuration of Cr?
67
What is the electron configuration of Mn?
68
What is the electron configuration of Fe?
69
What is the electron configuration of Co?
70
What is the electron configuration of Ni?
71
What is the electron configuration of Cu?
72
Describe the relationship bt/w acid strength an pKa + Ka?
The stronger the acid the higher Ka but lower pKa
73
What does the value of Kc tell you about where the equilibrium lies
- If Kc < 1 - equilibrium lies towards reactants
- If Kc = 1 - equilibrium lies midway bt/w reactants + products
- If Kc > 1 - equilibrium lies towards products
74
What factors affect + how Kc/Kp
- Temperature: If ↑temp shifts in endothermic direction, if bac reaction endothermic ↑ amount reactants + ↓ products - Kc/Kp ↓
- Depends on which way exo/endo can work it out by writing out equation, seeing if top or bottom ↓ then work out if that give you a bigger or smaller number (see p138)
- Concentration + pressure DO NOT affect Kc/Kp
75
Describe the set up of hydrogen-oxygen fuel cell
- Hydrogen is at the anode + oxidised
- Oxygen is at the cathode + reduced
76
What is the main difference bt/w acid or alkali hydrogen-oxygen fuel cell
Acid:
- H+ ions flow from left to right
Alkali:
- OH- ions flow from right to left
77
Which way does the equilibrium shift in electrode potentials?
- More positive E shifts forward/right
- More negative E shifts backward/left
78
Why do different elements have different enthalpy values?
- Due to their size
- The smaller ion will have greater enthalpy as have stronger attraction to ____
79
What must you talk about when asked why a buffer forms?
- ____ excess
- Equation
- Buffer contains ____ (acid) + ____ (A-)
- As acid partially neutralised
