Electomagnetic Radiation And Atomic Spectra Flashcards Preview

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Flashcards in Electomagnetic Radiation And Atomic Spectra Deck (151):
1

What is radiation ?
what is its wavelength and frequency

Energy
It has a high frequency and short wavelength.

2

What is frequency measured in ?

Hz or s-1

3

What is wavelength measured in ?

M or nm

4

How do you turn m into nm

Divide by 1x10-9

5

What is speed of light ?

3x10^8 ms-1

6

List all equations

C=fwavelength
E=lhc/wavelength
E=lhc where v is wave number and v =1/wavelength

7

What is Avogadro (l) measured in ?

Joules

8

How do you change joules to kilojoules

Divide by 1000

9

What is the difference between emission and absorption spectra ?

What is the more common term for convergence limit ?

Absorption spectra is the visible colours spectrum and it has thick black lines

Whereas the emission spectra is a black background with coloured lines.

Ionisation energy.

10

How is an emission spectra formed ?

To form an emission spectra an electron must be promoted from a low energy level to a higher energy level. This can be done by applying heat or electrical energy. Then the electron falls back down to the lower energy level by emitting energy in the form of photons. Draw diagram. Each line in the diagram represents radiation of a specific wavelength or frequency and from these the difference in energy can be calculated.

11

What is an orbital ?

It is a region of space where there is a high probability of finding an electron.

12

What are principal quantum numbers ?

They are used to label the energy levels.

The higher the principal quatum number the further away the level is from the nucleus represented by n

13

What are s orbitals

They are Spherical in shape and can hold 2 electrons

14

What are p orbitals

They are dumbbell shape and have 3 types X , y and z. They can hold a maximum of 6 electrons and are degenerate .

15

What does degenerate mean ?

They have the same energy

16

What are d orbitals ?

They can hold 10 electrons as there are 5 d orbitals. They are also degenerate.

17

What's the 3 rules about filling orbitals

Paul's exclusion principle
Aufbau principle
Hunds rule

18

What is paulis exclusion principle

This states that an orbital cannot contain more than 2 electrons and they must have opposite spins.

19

Aufbau principle?

This states that when electrons are placed into orbitals they must fill energy levels up from low energy to higher energy for example 1s will be filled before 2s.

20

Hunds rule ?

This states that when there is degenerate orbitals the electrons must fill each one singly with parallel spins before pairing.

21

What's the 2 anomalies in electron configuration why does it occur ?

Copper and chromium


Copper 1s2 2s2 2p6 3s2 3p6 4s1 3D10
Chromium is 1s2 2s2 2p6 3s2 3p6 4s1 3d5
Before wouldn't be stable arrangement

22

Are electrons removed from 4s or 3d first and why ?

4s as it has a lower energy

23

What has the highest ionisation energy and why ?

Noble gases as they have a complete p orbital in outer energy level which is stable

24

Why does be have higher ionisation tan boron

Draw orbital boxes and relies that be has full 2s orbital where as b has not full 2p


Be has higher ionisation energy as you are removing electrons from a full more stable 2s orbital so you need more energy compared b which is removing electrons from a not full 2p orbital which is less stable so requires less energy.

25

Why does nitrogen have higher ionisation than oxygen

Draw orbital box and realise that nitrogen has Half filled 2p while oxygen has full first 2p

Higher ionisation of nitrogen as it has a half filled 2p orbital which I'd more stable so requires more energy to remove electrons compared to oxygen Whig has a full first 2p orbital which results in repulsion making it easier to remove electrons.

26

What's the 2 types of electron pairs you can get

Bonding pair and lone pair

27

How do you prEdict the shape of a molecule. ?

Calculate the number of bonding pairs and lone pairs in the molecule , then use chart that's memorised to find shape

28

What shape is it if there's 2 bonding pairs

Linear

29

3 bonding

Trigonal planar

30

Bond angles of trigonal planar ?

120

31

4 bonding

Tetrahedral

32

Bond angles of tetrahedral ?

109.5

33

3 bonding 1 lone

Pyramidal

34

Bond angle pyramidal

107

35

2 bonding 2 lone

Bent

36

Bond angle in bent

104

37

5 bonding pairs

Trigonal bipyramidal

38

3 bonding 2 lone

T shape

39

6 bonding

Octahedral

40

5 bonding 1 lone

Square pyramid

41

4 bonding 2 lone

Square planar

42

When comparing ch4 ( 109.5) and nh3 (107) why difference in bond angle

Ch4 is larger the nh3 bond angle . This is because nh3 has a lone pair of electrons which causes most repulsion compared to the other bonding pairs.

43

What is angular momentum quantum number ?

Relates to the type of orbital represented by l

0123
S pdf

44

Magnetic quantum number ?

This is the orientation if the orbitals represented by m

Xyz
-10+1

45

Spin quantum number

This related to the spin of an orbital so either +1/2 or -1/2 represented by s

46

What is a dative covalent bond ?

When an atom provides both electrons in a covalent bond

47

What does an oxidation number indicate ?

The number of electrons lost, gained or shared as a result of chemical bonding.

48

How do you work out the oxidation. State for single atoms ?

Same as charge , look at the valency .

49

Oxidation number for compound ?

Set up algebraic equation to work out charge , must equal charge of ion

50

What is reduction in terms of oxidation number ?

oxidation number decreases

51

What is oxidation in terms of oxidation number ?

If oxidation number increases

52

What is a reducing agent ?

Always oxidized , lose electrons

53

What is oxidising agent

Electrons are gained as it is reduced

54

Where are the best reducing agents ?

Top right

55

Where are the best oxidising agents ?

The bottom left

56

What is a resonance structure ?

When there’s more than one equivalent form for one structure

57

What is a complex ?

Usually a positive central metal ion surrounded by Ligands

58

What are ligands ?

particles that are able to donate electrons in order to form a dative covalent bond.

This could be through lone pairs ie water and ammonia or having a negative charge

59

What’s the name of ligands that donate one pair of electrons ?

Monodentate is water and ammonia

60

What is a bidentate ligand

A ligand that donates 2 electron pairs but they must be on different parts of the molecule

61

Name other ligand classifications

Tridentate
Quadridentate
Pentadentate

62

What is a coordination number ?

The number of bonds of the Central ion.

63

How do you work out the coordination number ?

Count round central ion

64

Chloride ion ?

Cl-

Chloro

65

Oxide ion ?

O2- oxo

66

Cyanide ion ?

CN-

Cyano

67

Oxalate ion ?

C2O42-

Oxalato

68

Ammonia ?

Ammine

Nh3

69

Water

H20
Aqua

70

Carbon monoxide ?

CO

Carbonyl

71

How do you name ligand ?

Prefix for ligand , name of ligand

If negative ligands then add ate for Latin names.

72

If vanadium is negative

Vandate

73

If chromium is negative

Chromate

74

Manganese

Manganate

75

Iron

FeRRate

76

Cobalt

Cobaltate

77

Nickel

Nickelate

78

Copper

Cuprate

79

Tin

StaNNate

80

Lead

Plumbate

81

How do you name complex ?

In square brackets
Name ligand first with prefix first
Metal
Oxidation state of metal
Write ion

82

Why are some complex ions coloured ?

The ion absorbs light in certain parts of the visible spectrum.
The remaining wavelengths are transmitted
The colour seen is the complimentary colour to the colour absorbed

83

Why do transition metals or ions absorb light ?

Due to d-d orbital splitting. In a transition metal or ion the five d orbitals are degenerate. The ligands surrounding the central ion will affect the energy of the d orbitals.
The ligands will donate their electrons into the d orbitals that lie on the axis this causes the d orbitals to rise in energy while the other orbitals are unaffected. Transition metals absorb light because photons excite the lower d orbitals up to a higher energy levels.

84

What affects the splitting of the d orbitals ?

The nature of the ligands

85

What is a heterogeneous catalyst

A catalyst that is in a different state to the reactants

86

What is a homogeneous catalyst

A catalyst that is in the same state as the reactants

87

What occurs during adsorption

Molecules of one or both of the reactants forms bonds with the catalyst and this weakens the bonds within the molecule

88

What occurs during reaction

The molecules react on the catalyst surface, the angle of collision is more likely to be favourable as one of the molecules is fixed.

89

What occurs during desorption

The reactant molecules leave the catalyst and the active site becomes vacant ready for another reactants molecule.

90

What is the definition of equilibrium?

When the rate of the forward reaction is equal to the rate of the backwards reaction. The concentration of the products and reactants constant but not equal.

91

What is the equilibrium constant shown by ?

Capital k

92

What is the expression for K

aA+bB__> cC+dD

K=[C]c[D]d
----------
[A]a[B]b

93

What is the units of K

No units

94

In K what is value of 1

Pure liquids and solids such as water

95

WHat does a high value of k ( above 1) tell you about the reaction?

That there is a higher percentage of products in the equilibrium

96

What does it tell you about the reaction if k is 1

Equilibrium lies neither to the left or the right , similar amounts of products and reactants

97

K is smaller than 1

Higher percentage of reactants in reactants in the equilibrium

98

What is partial pressure ?

The pressure exerted by gas when it is alone in a space of volume

99

Does a catalyst effect the equilibrium?

No it does not therefor it doesn't alter the value of K

100

What is the only thing that alters the value of k ?

Temperature

101

What is the ionic product of water ?

When there's an equal number of 0H ions to h ions represented by Kw

102

What effect does increasing the temperature have on the ionic product of water Kw

It increases it and increases the dissociation

103

What is the formula for nitric acid ??

HN03

104

Carbonic acid

H2CO3

105

Sulphuric

H2SO4

106

Phosphoric

H3PO4

107

What is a strong acid

An acid that dissociates completely in a solution

108

List strong acids

Hydrochloride HCL
Sulphuric h2so4
Nitric HNO3

109

What is a weak acid

An acid that dissociated partially in a solution

110

List weak acids

All carboxylic acids
PhosphORIC H3po4
Sulphurous h2so3
Carbonic h2co3

111

What is a weak base

It is a base that doesn't dissociate completely in a solution

112

Give an example of a weak base

Ammonium hydroxide

113

What is a strong base

A base that dissociates completely in a solution

114

Give example strong base

All exempt ammonium hydroxide ie lithium hydroxide , potassium hydroxide

115

What is the base and acid if an acidic salt ?

Strong acid and weak base

116

What is the base and avid of an alkaline salt ?

Strong base and weak acid

117

What is base and acid of neutral salt ?

Strong acid and base

118

What is an acid

Proton donor

119

What is an. Alkali

Proton acceptor

120

What do you call a substance that acts as an acid and a base

Amphoteric

121

What is a conjugate base ?

Whatever is left of the acid ( negative)

122

What is a conjugate acid ?

Whatever if left of the base after it accepts a hydrogen ( positive )

123

What is a buffer solution ?

It's a solution which the pH remains approximately constant even when small amounts of acids and bases are added to the solution

124

What's in an acidic buffer ?

Strong base , weak acid and salt of weak acid

125

What is an alkaline buffer ?

Weak base , strong acid and salt if weak base

126

Why are indicators used ?

They are used in acid base titrTions as they change colour at the end point

127

What are indicators usually ?

Weak acids that are different in colour to the conjugate base

128

What is standard enthalpy of formation ?

When a compound is formed from its elements in their usual room temperature state

129

What is standard temperature in kelvins

298K

130

What is entropy ?

It's the amount of disorder in a system

131

What's the entropy of a perfect crystal and why ?

Zero as there is no motion at all

132

What has happened to the entropy of a reaction if the s is negative

Decreased

133

What has happened to the entropy of a reaction if the s is positive

Increased

134

What is a spontaneous or feasible reaction ?

A reaction that proceeds towards the products rather than the reactants

135

How is a reaction feasible in terms of total entropy ?

The total entropy must be positive .

136

How is a reaction feasible in terms of Gibbs energy

Must be negative

137

What do you need to do in Gibbs

Change standard entropy change (s) must be divided by 1000

138

What the units of Gibbs

kJmol-1

139

If 2 positive in Gibbs what temp will make feasible

High

140

If 2 negative in Gibbs what temp will make it feasible

Low

141

How do you work out temperature of feasible reaction

Sub Gibbs is o into equation t = h over s

142

What if Gibbs in reversible reaction

O

143

What is unit of rate equation

Small k

144

What is zero order

When changing concentration of one of he reactants has no effect in the rate of the reaction

145

What is first order

When doubling the concentration doubles the rate or triples the concept traction triples the rate

146

What is second order

When doubling the concentration quadruples the rate

147

Units of 1st order.

S-1 or min-1

148

Units 2nd order

Mol-1ls-1 or mol-1lmin-1

149

Units 3rd order

Mil-2l2s-1 or moo-2l2min

150

What is the slowest step in a reaction

The rate determining step

151

What is reaction mechanisms

The concept that most reaction occur in a series of small steps