Paper 5 Flashcards Preview

Chemistry A2 > Paper 5 > Flashcards

Flashcards in Paper 5 Deck (70):
0

Rate of reaction

The change in conc of a reactant or product per unit time

1

Rate =

k[A]m[B]n
Can on,y be determined practically by experiment

2

Overall order

M+n

3

Half life

The time taken for the concentration of a reactant to reduce by half

4

Initial rate

The rate right at the start of a reaction (t=0)

5

Rate determining step

The slowest step in the mechanism of a multi-step reaction

6

An intermediate

Used up in one step of the reaction and formed in a subsequent step. Not seen as a product or reactant in the overall equation.

7

Kc=

[prod]/[react]

8

pH=

-log[H+]

9

pKa=

-logKa

10

[H+]=

10^-pH

11

Ka=

10^-pKa

12

Ionic product of water (Kw)

Kc = [H+][OH-]/[H2O]
Eq to left so v small
Kc x [H2O] = Kw = [H+][OH-]

13

Buffer

A solution able to oppose changes in pH when small quantities of acid or base are added
(Weak acid and conjugate base)

14

Enthalpy of neutralisation

The enthalpy change when an aqueous acid reacts with an aqueous base to form 1 mole of water under standard conditions (100kPa, 298K)

15

Equivalence point

The point in a titration at which the volume of one solution has reacted exactly with the volume of the second solution matching the stoichiometric of the reaction

16

Hess' Law

States that if a reaction can take place by more that one route and the initial and final conditions and the same, the total enthalpy change is the same for each route.

17

Lattice enthalpy (LE)

The enthalpy change when 1 mole of a solid ionic compound is formed from its gaseous ions under standard conditions (298K, 100kPa).
e.g. K+(g) + Cl-(g) ➡️ KCl(s)

18

Standard enthalpy change of formation (

The enthalpy change when 1 mole of a compound is formed from its constituent elements in their standard States under standard conditions (298K, 100kPa)
e.g. K(s) + 1/2Cl2(g) ➡️ KCl(s)
-

19

Standard enthalpy change of atomisation (

The enthalpy change when 1 mole of gaseous atoms forms from the elements in their standard states under standard conditions (298K, 100kPa)
e.g. 1/2Cl2(g) ➡️ Cl(g)
+

20

First ionisation energy (

The enthalpy change when 1 electron is removed from each atoms in 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions.
e.g. Cl(g) ➡️ Cl+(g) + e-

21

Second ionisation energy (

The enthalpy change when 1 electron is removed from each ion in 1 mole of 1+ gaseous ions to form 1 mole of gaseous 2+ ions.
e.g. Ca+(g) ➡️ Ca2+(g) + e-

22

First electron affinity (

The enthalpy change when 1 electron is added to each atom in 1 mo,e of gaseous atoms forming 1 mole of gaseous 1- ions.
e.g. Cl(g) + e- ➡️ Cl-(g)
-

23

Second electron affinity (

The enthalpy change when 1 electron is added to each ion in 1 mole of gaseous 1- ions forming 1 mole of gaseous 2- ions.
e.g. O-(g) + e- ➡️ O2-(g)
+

24

Born-Haber cycles

Used to calculate enthalpy change that cannot be measured direct,y.

25

Standard enthalpy change of solution (

The enthalpy change when 1 mole of a compound is fully dissolved in water under standard conditions (298K, 100kPa)
e.g. KCl(s) ➡️ K+(aq) + Cl-(aq)
+/-

26

Standard enthalpy change of hydration (

The enthalpy change when 1 mole of aqueous ions are formed from gaseous ions under standard conditions (298K, 100kPa).
e.g. K+(g) + aq ➡️ K+(aq)
+

27

Standard entropy change of a reaction (

The entropy change of a reaction in the molar quantities expressed in th equation under standard conditions (298K, 100kPa) in standard States.

28

Standard entropy of a substance (S⚪️)
P

The entropy content of 1 mole of a substance under standard conditions (298K, 100kPa).

29

sum of products - sum of reactants

30

The overall energy or Gibb's free energy of a system (G)

Results from the contributions of both enthalpy and entropy

31

32

Oxidation

The gain of oxygen or hydrogen, the loss of electrons or the increase in oxidation number.

33

Reduction

The loss of oxygen or hydrogen, the gain of electrons or the decrease in oxidation number.

34

Oxidation number of elements

0

35

Oxidation number of combined group 1 atoms

+1

36

Oxidation number of combined group 2 atoms

+2

37

Oxidation number of aluminum

+3

38

Oxidation number of hydrogen

+1

39

Oxidation number of flourine

-1

40

Oxidation number of oxygen

-2

41

Oxidation number of chlorine, bromine and iodine

-1

42

Order of priority of oxidation numbers

Elements 0
Group 1 +1
Group 2 +2
Aluminium +3
Hydrogen +1
Flourine -1
Oxygen -2
Cl, Br, I -1

43

Standard electrode potential of a half cell (E⚪️)

The electromotive force (e.m.f.) of a half cell compared with a standard hydrogen half cell, measured at 298K with solution concentrations of 1 moldm-3 and a gas pressure of 100kPa (1 atmosphere).

44

Transition metal

A d-block element that forms at least one ion with an incomplete d sub-shell.

45

Precipitation reaction

2 solutions mixed together to produce an insoluble product

46

Copper (II) hydroxide precipitation reaction

Cu2+(aq) + 2OH-(aq) ➡️ Cu(OH)2(s)
Cu2+ pale blue ➡️ pale blue precipitate (beige in air)

47

Cobalt (II) hydroxide precipitation reaction

Co2+(aq) + 2OH-(aq) ➡️ Co(OH)2(s)
Co2+ pink ➡️ blue precipitate

48

Iron (II) hydroxide precipitation reaction

Fe2+(aq) + 2OH-(aq) ➡️ Fe(OH)2(s)
Fe2+ pale green ➡️ green precipitate (rusty-brown in air)

49

Iron (III) hydroxide precipitation reaction

Fe3+(aq) + 3OH-(aq) ➡️ Fe(OH)3
Fe3+ pale yellow ➡️ rusty-brown precipitate

50

Complex ion

A central transition metal ion bonded to one or more Luganda by coordinate bonds (dative covalent bonds).

51

Ligand

An ion, molecule or atom with a lone pair of electrons that can be donated to a transition metal to form a coordinate bond.

52

Co-ordination number

The total number of coordinate bonds between a central metal ion and its ligands.

53

Monodentate ligand

A ligand that donates one pair of electrons to the central metal ion

54

A bidentate ligand

Donates two lone pairs of electrons to the central transition metal ion, forming two co-ordinate bonds.

55

Shape of 6 co-ordinate bonds?

Octahedral
90 degrees

56

4 co-ordinate bonds shape?

Tetrahedral - 109.5 degrees
For nickel, palladium or platinum - 90 degrees

57

Ligand substitution

A reaction in which one ligand in a complex ion is replaced by another ligand.

58

Cis-trans isomerism

Cis - 90 degrees
Trans - 180 degrees

59

Optical isomerism

Non-superimposable mirror images that rotate plane polarised by equal amounts in opposite directions.
Have no plane of symmetry.

60

Cis-platin

[PtCl2(NH3)2]
An anti-can we drug that binds to cancer cells' DNA and prevents division as it alters the structure.

61

Stability constant

The equilibrium constant for the formation of the complex ion from its constituent ions

62

Kstab=

[products]/[formation]
Ignoring water
Large = equilibrium to right = more stable

63

Hydrogen fuel cell equations

H2 ➡️ 2H+ + 2e-
1/2O2 + 2H+ + 2e- ➡️ H2O

2H2 + O2 ➡️ 2H2O

64

[Cu(H2O)6] 2+

Blue

65

[CuCl4]2-

Yellow

66

[Cu(NH3)4(H2O)2]2+

Deep blue

67

[Co(H2O)6]2+

Pink

68

[CoCl4]2-

Blue

69

PH of buffer

pKa + log([A-]/[HA])